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Difference between revisions of "2010 AMC 10B Problems"

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 +
{{AMC10 Problems|year=2010|ab=B}}
 
== Problem 1 ==
 
== Problem 1 ==
 
+
What is <math>100(100-3)-(100\cdot100-3)</math>?
  
 
<math>
 
<math>
\mathrm{(A)}\  
+
\textbf{(A)}\ -20,000
 
\qquad
 
\qquad
\mathrm{(B)}\  
+
\textbf{(B)}\ -10,000
 
\qquad
 
\qquad
\mathrm{(C)}\  
+
\textbf{(C)}\ -297
 
\qquad
 
\qquad
\mathrm{(D)}\  
+
\textbf{(D)}\ -6
 
\qquad
 
\qquad
\mathrm{(E)}\  
+
\textbf{(E)}\ 0
 
</math>
 
</math>
  
Line 19: Line 20:
 
== Problem 2 ==
 
== Problem 2 ==
  
 +
Makayla attended two meetings during her <math>9</math>-hour work day. The first meeting took <math>45</math> minutes and the second meeting took twice as long. What percent of her work day was spent attending meetings?
  
<math>
+
<math>\textbf{(A)}\ 15 \qquad \textbf{(B)}\ 20 \qquad \textbf{(C)}\ 25 \qquad \textbf{(D)}\ 30 \qquad \textbf{(E)}\ 35</math>
\mathrm{(A)}\  
 
\qquad
 
\mathrm{(B)}\  
 
\qquad
 
\mathrm{(C)}\  
 
\qquad
 
\mathrm{(D)}\  
 
\qquad
 
\mathrm{(E)}\  
 
</math>
 
  
 
[[2010 AMC 10B Problems/Problem 2|Solution]]
 
[[2010 AMC 10B Problems/Problem 2|Solution]]
  
 
== Problem 3 ==
 
== Problem 3 ==
 +
A drawer contains red, green, blue, and white socks with at least 2 of each color. What is
 +
the minimum number of socks that must be pulled from the drawer to guarantee a matching
 +
pair?
  
 
<math>
 
<math>
\mathrm{(A)}\  
+
\textbf{(A)}\ 3
 
\qquad
 
\qquad
\mathrm{(B)}\  
+
\textbf{(B)}\ 4
 
\qquad
 
\qquad
\mathrm{(C)}\  
+
\textbf{(C)}\ 5
 
\qquad
 
\qquad
\mathrm{(D)}\  
+
\textbf{(D)}\ 8
 
\qquad
 
\qquad
\mathrm{(E)}\  
+
\textbf{(E)}\ 9
 
</math>
 
</math>
  
Line 51: Line 46:
  
 
== Problem 4 ==
 
== Problem 4 ==
 
+
For a real number <math>x</math>, define <math>\heartsuit(x)</math> to be the average of <math>x</math> and <math>x^2</math>. What is <math>\heartsuit(1)+\heartsuit(2)+\heartsuit(3)</math>?
  
 
<math>
 
<math>
\mathrm{(A)}\  
+
\textbf{(A)}\ 3
 
\qquad
 
\qquad
\mathrm{(B)}\  
+
\textbf{(B)}\ 6
 
\qquad
 
\qquad
\mathrm{(C)}\  
+
\textbf{(C)}\ 10
 
\qquad
 
\qquad
\mathrm{(D)}\  
+
\textbf{(D)}\ 12
 
\qquad
 
\qquad
\mathrm{(E)}\  
+
\textbf{(E)}\ 20
 
</math>
 
</math>
  
Line 70: Line 65:
  
  
<math>
+
A month with <math>31</math> days has the same number of Mondays and Wednesdays. How many of the seven days of the week could be the first day of this month?
\mathrm{(A)}\  
+
 
\qquad
+
<math>\textbf{(A)}\ 2 \qquad \textbf{(B)}\ 3 \qquad \textbf{(C)}\ 4 \qquad \textbf{(D)}\ 5 \qquad \textbf{(E)}\ 6</math>
\mathrm{(B)}\  
 
\qquad
 
\mathrm{(C)}\  
 
\qquad
 
\mathrm{(D)}\  
 
\qquad
 
\mathrm{(E)}\  
 
</math>
 
  
 
[[2010 AMC 10B Problems/Problem 5|Solution]]
 
[[2010 AMC 10B Problems/Problem 5|Solution]]
Line 86: Line 73:
 
== Problem 6 ==
 
== Problem 6 ==
  
 +
A circle is centered at <math>O</math>, <math>\overline{AB}</math> is a diameter and <math>C</math> is a point on the circle with <math>\angle COB = 50^\circ</math>.
 +
What is the degree measure of <math>\angle CAB</math>?
  
 
<math>
 
<math>
\mathrm{(A)}\  
+
\textbf{(A)}\ 20
 
\qquad
 
\qquad
\mathrm{(B)}\  
+
\textbf{(B)}\ 25
 
\qquad
 
\qquad
\mathrm{(C)}\  
+
\textbf{(C)}\ 45
 
\qquad
 
\qquad
\mathrm{(D)}\  
+
\textbf{(D)}\ 50
 
\qquad
 
\qquad
\mathrm{(E)}\  
+
\textbf{(E)}\ 65
 
</math>
 
</math>
  
Line 103: Line 92:
 
== Problem 7 ==
 
== Problem 7 ==
  
 +
A triangle has side lengths <math>10</math>, <math>10</math>, and <math>12</math>. A rectangle has width <math>4</math> and area equal to the
 +
area of the triangle. What is the perimeter of this rectangle?
  
 
<math>
 
<math>
\mathrm{(A)}\  
+
\textbf{(A)}\ 16
 
\qquad
 
\qquad
\mathrm{(B)}\  
+
\textbf{(B)}\ 24
 
\qquad
 
\qquad
\mathrm{(C)}\  
+
\textbf{(C)}\ 28
 
\qquad
 
\qquad
\mathrm{(D)}\  
+
\textbf{(D)}\ 32
 
\qquad
 
\qquad
\mathrm{(E)}\  
+
\textbf{(E)}\ 36
 
</math>
 
</math>
  
Line 120: Line 111:
 
== Problem 8 ==
 
== Problem 8 ==
  
 +
A ticket to a school play cost <math>x</math> dollars, where <math>x</math> is a whole number. A group of 9th graders buys tickets costing a total of <math>\textdollar 48</math>, and a group of 10th graders buys tickets costing a total of <math>\textdollar 64</math>. How many values for <math>x</math> are possible?
  
<math>
+
<math>\textbf{(A)}\ 1 \qquad \textbf{(B)}\ 2 \qquad \textbf{(C)}\ 3 \qquad \textbf{(D)}\ 4 \qquad \textbf{(E)}\ 5</math>
\mathrm{(A)}\
 
\qquad
 
\mathrm{(B)}\  
 
\qquad
 
\mathrm{(C)}\  
 
\qquad
 
\mathrm{(D)}\  
 
\qquad
 
\mathrm{(E)}\  
 
</math>
 
  
 
[[2010 AMC 10B Problems/Problem 8|Solution]]
 
[[2010 AMC 10B Problems/Problem 8|Solution]]
Line 137: Line 119:
 
== Problem 9 ==
 
== Problem 9 ==
  
 +
Lucky Larry's teacher asked him to substitute numbers for <math>a</math>, <math>b</math>, <math>c</math>, <math>d</math>, and <math>e</math> in the expression <math>a-(b-(c-(d+e)))</math> and evaluate the result. Larry ignored the parentheses but added and subtracted correctly and obtained the correct result by coincidence. The numbers Larry substituted for <math>a</math>, <math>b</math>, <math>c</math>, and <math>d</math> were <math>1</math>, <math>2</math>, <math>3</math>, and <math>4</math>, respectively. What number did Larry substitute for <math>e</math>?
  
<math>
+
<math>\textbf{(A)}\ -5 \qquad \textbf{(B)}\ -3 \qquad \textbf{(C)}\ 0 \qquad \textbf{(D)}\ 3 \qquad \textbf{(E)}\ 5</math>
\mathrm{(A)}\  
 
\qquad
 
\mathrm{(B)}\  
 
\qquad
 
\mathrm{(C)}\  
 
\qquad
 
\mathrm{(D)}\  
 
\qquad
 
\mathrm{(E)}\  
 
</math>
 
  
 
[[2010 AMC 10B Problems/Problem 9|Solution]]
 
[[2010 AMC 10B Problems/Problem 9|Solution]]
Line 154: Line 127:
 
== Problem 10 ==
 
== Problem 10 ==
  
 +
Shelby drives her scooter at a speed of <math>30</math> miles per hour if it is not raining, and <math>20</math> miles per hour if it is raining. Today she drove in the sun in the morning and in the rain in the evening, for a total of <math>16</math> miles in <math>40</math> minutes. How many minutes did she drive in the rain?
  
<math>
+
<math>\textbf{(A)}\ 18 \qquad \textbf{(B)}\ 21 \qquad \textbf{(C)}\ 24 \qquad \textbf{(D)}\ 27 \qquad \textbf{(E)}\ 30</math>
\mathrm{(A)}\  
 
\qquad
 
\mathrm{(B)}\  
 
\qquad
 
\mathrm{(C)}\  
 
\qquad
 
\mathrm{(D)}\  
 
\qquad
 
\mathrm{(E)}\  
 
</math>
 
  
 
[[2010 AMC 10B Problems/Problem 10|Solution]]
 
[[2010 AMC 10B Problems/Problem 10|Solution]]
  
 
== Problem 11 ==
 
== Problem 11 ==
 
+
A shopper plans to purchase an item that has a listed price greater than <math>\textdollar 100</math> and can use any one of the three coupons. Coupon A gives <math>15\%</math> off the listed price, Coupon B gives <math>\textdollar 30</math> off the listed price, and Coupon C gives <math>25\%</math> off the amount by which the listed price exceeds
 +
<math>\textdollar 100</math>. <br/>
 +
Let <math>x</math> and <math>y</math> be the smallest and largest prices, respectively, for which Coupon A saves at least as many dollars as Coupon B or Coupon C. What is <math>y - x</math>?
  
 
<math>
 
<math>
\mathrm{(A)}\  
+
\textbf{(A)}\ 50
 
\qquad
 
\qquad
\mathrm{(B)}\  
+
\textbf{(B)}\ 60
 
\qquad
 
\qquad
\mathrm{(C)}\  
+
\textbf{(C)}\ 75
 
\qquad
 
\qquad
\mathrm{(D)}\  
+
\textbf{(D)}\ 80
 
\qquad
 
\qquad
\mathrm{(E)}\  
+
\textbf{(E)}\ 100
 
</math>
 
</math>
  
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== Problem 12 ==
 
== Problem 12 ==
  
 +
At the beginning of the school year, <math>50\%</math> of all students in Mr. Wells' math class answered "Yes" to the question "Do you love math", and <math>50\%</math> answered "No." At the end of the school year, <math>70\%</math> answered "Yes" and <math>30\%</math> answered "No." Altogether, <math>x\%</math> of the students gave a different answer at the beginning and end of the school year. What is the difference between the maximum and the minimum possible values of <math>x</math>?
  
<math>
+
<math>\textbf{(A)}\ 0 \qquad \textbf{(B)}\ 20 \qquad \textbf{(C)}\ 40 \qquad \textbf{(D)}\ 60 \qquad \textbf{(E)}\ 80</math>
\mathrm{(A)}\  
 
\qquad
 
\mathrm{(B)}\  
 
\qquad
 
\mathrm{(C)}\  
 
\qquad
 
\mathrm{(D)}\  
 
\qquad
 
\mathrm{(E)}\  
 
</math>
 
  
 
[[2010 AMC 10B Problems/Problem 12|Solution]]
 
[[2010 AMC 10B Problems/Problem 12|Solution]]
  
 
== Problem 13 ==
 
== Problem 13 ==
 
+
What is the sum of all the solutions of <math>x = \left|2x-|60-2x|\right|</math>?
  
 
<math>
 
<math>
\mathrm{(A)}\  
+
\textbf{(A)}\ 32
 
\qquad
 
\qquad
\mathrm{(B)}\  
+
\textbf{(B)}\ 60
 
\qquad
 
\qquad
\mathrm{(C)}\  
+
\textbf{(C)}\ 92
 
\qquad
 
\qquad
\mathrm{(D)}\  
+
\textbf{(D)}\ 120
 
\qquad
 
\qquad
\mathrm{(E)}\  
+
\textbf{(E)}\ 124
 
</math>
 
</math>
  
Line 222: Line 179:
 
== Problem 14 ==
 
== Problem 14 ==
  
 +
The average of the numbers <math>1, 2, 3,\cdots, 98, 99,</math> and <math>x</math> is <math>100x</math>. What is <math>x</math>?
  
<math>
+
<math>\textbf{(A)}\ \dfrac{49}{101} \qquad \textbf{(B)}\ \dfrac{50}{101} \qquad \textbf{(C)}\ \dfrac{1}{2} \qquad \textbf{(D)}\ \dfrac{51}{101} \qquad \textbf{(E)}\ \dfrac{50}{99}</math>
\mathrm{(A)}\  
 
\qquad
 
\mathrm{(B)}\  
 
\qquad
 
\mathrm{(C)}\  
 
\qquad
 
\mathrm{(D)}\  
 
\qquad
 
\mathrm{(E)}\  
 
</math>
 
  
 
[[2010 AMC 10B Problems/Problem 14|Solution]]
 
[[2010 AMC 10B Problems/Problem 14|Solution]]
  
 
== Problem 15 ==
 
== Problem 15 ==
 
+
On a <math>50</math>-question multiple choice math contest, students receive <math>4</math> points for a correct answer, <math>0</math> points for an answer left blank, and <math>-1</math> point for an incorrect answer. Jesse’s total score on the contest was <math>99</math>. What is the maximum number of questions that Jesse could have answered correctly?
  
 
<math>
 
<math>
\mathrm{(A)}\  
+
\textbf{(A)}\ 25
 
\qquad
 
\qquad
\mathrm{(B)}\  
+
\textbf{(B)}\ 27
 
\qquad
 
\qquad
\mathrm{(C)}\  
+
\textbf{(C)}\ 29
 
\qquad
 
\qquad
\mathrm{(D)}\  
+
\textbf{(D)}\ 31
 
\qquad
 
\qquad
\mathrm{(E)}\  
+
\textbf{(E)}\ 33
 
</math>
 
</math>
  
Line 255: Line 203:
  
 
== Problem 16 ==
 
== Problem 16 ==
 
+
A square of side length <math>1</math> and a circle of radius <math>\dfrac{\sqrt{3}}{3}</math> share the same center. What is the area inside the circle, but outside the square?
  
 
<math>
 
<math>
\mathrm{(A)}\  
+
\textbf{(A)}\ \dfrac{\pi}{3}-1
 
\qquad
 
\qquad
\mathrm{(B)}\  
+
\textbf{(B)}\ \dfrac{2\pi}{9}-\dfrac{\sqrt{3}}{3}
 
\qquad
 
\qquad
\mathrm{(C)}\  
+
\textbf{(C)}\ \dfrac{\pi}{18}
 
\qquad
 
\qquad
\mathrm{(D)}\  
+
\textbf{(D)}\ \dfrac{1}{4}
 
\qquad
 
\qquad
\mathrm{(E)}\  
+
\textbf{(E)}\ \dfrac{2\pi}{9}
 
</math>
 
</math>
  
Line 272: Line 220:
  
 
== Problem 17 ==
 
== Problem 17 ==
 +
Every high school in the city of Euclid sent a team of <math>3</math> students to a math contest. Each participant in the contest received a different score. Andrea's score was the median among all students, and hers was the highest score on her team. Andrea's teammates Beth and Carla placed <math>37</math>th and <math>64</math>th, respectively. How many schools are in the city?
  
 
+
<math>\textbf{(A)}\ 22 \qquad \textbf{(B)}\ 23 \qquad \textbf{(C)}\ 24 \qquad \textbf{(D)}\ 25 \qquad \textbf{(E)}\ 26</math>
<math>
 
\mathrm{(A)}\  
 
\qquad
 
\mathrm{(B)}\  
 
\qquad
 
\mathrm{(C)}\  
 
\qquad
 
\mathrm{(D)}\  
 
\qquad
 
\mathrm{(E)}\  
 
</math>
 
  
 
[[2010 AMC 10B Problems/Problem 17|Solution]]
 
[[2010 AMC 10B Problems/Problem 17|Solution]]
Line 290: Line 228:
 
== Problem 18 ==
 
== Problem 18 ==
  
 +
Positive integers <math>a</math>, <math>b</math>, and <math>c</math> are randomly and independently selected with replacement from the set <math>\{1, 2, 3,\dots, 2010\}</math>. What is the probability that <math>abc + ab + a</math> is divisible by <math>3</math>?
  
 
+
<math>\textbf{(A)}\ \dfrac{1}{3} \qquad \textbf{(B)}\ \dfrac{29}{81} \qquad \textbf{(C)}\ \dfrac{31}{81} \qquad \textbf{(D)}\ \dfrac{11}{27} \qquad \textbf{(E)}\ \dfrac{13}{27}</math>
<math>
 
\mathrm{(A)}\  
 
\qquad
 
\mathrm{(B)}\  
 
\qquad
 
\mathrm{(C)}\  
 
\qquad
 
\mathrm{(D)}\  
 
\qquad
 
\mathrm{(E)}\  
 
</math>
 
  
 
[[2010 AMC 10B Problems/Problem 18|Solution]]
 
[[2010 AMC 10B Problems/Problem 18|Solution]]
Line 308: Line 236:
 
== Problem 19 ==
 
== Problem 19 ==
  
 
+
A circle with center <math>O</math> has area <math>156\pi</math>. Triangle <math>ABC</math> is equilateral, <math>\overline{BC}</math> is a chord on the circle, <math>OA = 4\sqrt{3}</math>, and point <math>O</math> is outside <math>\triangle ABC</math>. What is the side length of <math>\triangle ABC</math>?
  
 
<math>
 
<math>
\mathrm{(A)}\  
+
\textbf{(A)}\ 2\sqrt{3}
 
\qquad
 
\qquad
\mathrm{(B)}\  
+
\textbf{(B)}\ 6
 
\qquad
 
\qquad
\mathrm{(C)}\  
+
\textbf{(C)}\ 4\sqrt{3}
 
\qquad
 
\qquad
\mathrm{(D)}\  
+
\textbf{(D)}\ 12
 
\qquad
 
\qquad
\mathrm{(E)}\  
+
\textbf{(E)}\ 18
 
</math>
 
</math>
  
Line 326: Line 254:
 
== Problem 20 ==
 
== Problem 20 ==
  
 +
Two circles lie outside regular hexagon <math>ABCDEF</math>. The first is tangent to <math>\overline{AB}</math>, and the second is tangent to <math>\overline{DE}</math>. Both are tangent to lines <math>BC</math> and <math>FA</math>. What is the ratio of the area of the second circle to that of the first circle?
  
 
<math>
 
<math>
\mathrm{(A)}\  
+
\textbf{(A)}\ 18
 
\qquad
 
\qquad
\mathrm{(B)}\  
+
\textbf{(B)}\ 27
 
\qquad
 
\qquad
\mathrm{(C)}\  
+
\textbf{(C)}\ 36
 
\qquad
 
\qquad
\mathrm{(D)}\  
+
\textbf{(D)}\ 81
 
\qquad
 
\qquad
\mathrm{(E)}\  
+
\textbf{(E)}\ 108
 
</math>
 
</math>
  
Line 344: Line 273:
  
  
 +
A palindrome between <math>1000</math> and <math>10,000</math> is chosen at random. What is the probability that it is divisible by <math>7</math>?
  
<math>
+
<math>\textbf{(A)}\ \dfrac{1}{10} \qquad \textbf{(B)}\ \dfrac{1}{9} \qquad \textbf{(C)}\ \dfrac{1}{7} \qquad \textbf{(D)}\ \dfrac{1}{6} \qquad \textbf{(E)}\ \dfrac{1}{5}</math>
\mathrm{(A)}\  
 
\qquad
 
\mathrm{(B)}\  
 
\qquad
 
\mathrm{(C)}\  
 
\qquad
 
\mathrm{(D)}\  
 
\qquad
 
\mathrm{(E)}\  
 
</math>
 
  
 
[[2010 AMC 10B Problems/Problem 21|Solution]]
 
[[2010 AMC 10B Problems/Problem 21|Solution]]
Line 361: Line 281:
 
== Problem 22 ==
 
== Problem 22 ==
  
 +
Seven distinct pieces of candy are to be distributed among three bags. The red bag and the blue bag must each receive at least one piece of candy; the white bag may remain empty. How many arrangements are possible?
  
 
<math>
 
<math>
\mathrm{(A)}\  
+
\textbf{(A)}\ 1930
 
\qquad
 
\qquad
\mathrm{(B)}\  
+
\textbf{(B)}\ 1931
 
\qquad
 
\qquad
\mathrm{(C)}\  
+
\textbf{(C)}\ 1932
 
\qquad
 
\qquad
\mathrm{(D)}\  
+
\textbf{(D)}\ 1933
 
\qquad
 
\qquad
\mathrm{(E)}\  
+
\textbf{(E)}\ 1934
 
</math>
 
</math>
  
Line 377: Line 298:
  
 
== Problem 23 ==
 
== Problem 23 ==
 +
The entries in a <math>3 \times 3</math> array include all the digits from <math>1</math> through <math>9</math>, arranged so that the entries in every row and column are in increasing order. How many such arrays are there?
  
 
+
<math>\textbf{(A)}\ 18 \qquad \textbf{(B)}\ 24 \qquad \textbf{(C)}\ 36 \qquad \textbf{(D)}\ 42 \qquad \textbf{(E)}\ 60</math>
<math>
 
\mathrm{(A)}\  
 
\qquad
 
\mathrm{(B)}\  
 
\qquad
 
\mathrm{(C)}\  
 
\qquad
 
\mathrm{(D)}\  
 
\qquad
 
\mathrm{(E)}\  
 
 
 
</math>
 
  
 
[[2010 AMC 10B Problems/Problem 23|Solution]]
 
[[2010 AMC 10B Problems/Problem 23|Solution]]
Line 396: Line 306:
 
== Problem 24 ==
 
== Problem 24 ==
  
 +
A high school basketball game between the Raiders and Wildcats was tied at the end of the first quarter. The number of points scored by the Raiders in each of the four quarters formed an increasing geometric sequence, and the number of points scored by the Wildcats in each of the four quarters formed an increasing arithmetic sequence. At the end of the fourth quarter, the Raiders had won by one point. Neither team scored more than <math>100</math> points. What was the total number of points scored by the two teams in the first half?
  
<math>
+
<math>\textbf{(A)}\ 30 \qquad \textbf{(B)}\ 31 \qquad \textbf{(C)}\ 32 \qquad \textbf{(D)}\ 33 \qquad \textbf{(E)}\ 34</math>
\mathrm{(A)}\  
 
\qquad
 
\mathrm{(B)}\  
 
\qquad
 
\mathrm{(C)}\  
 
\qquad
 
\mathrm{(D)}\  
 
\qquad
 
\mathrm{(E)}\  
 
</math>
 
  
 
[[2010 AMC 10B Problems/Problem 24|Solution]]
 
[[2010 AMC 10B Problems/Problem 24|Solution]]
Line 413: Line 314:
 
== Problem 25 ==
 
== Problem 25 ==
  
 +
Let <math>a > 0</math>, and let <math>P(x)</math> be a polynomial with integer coefficients such that
 +
 +
<center>
 +
<math>P(1) = P(3) = P(5) = P(7) = a</math>, and<br/>
 +
<math>P(2) = P(4) = P(6) = P(8) = -a</math>.
 +
</center>
 +
 +
What is the smallest possible value of <math>a</math>?
  
<math>
+
<math>\textbf{(A)}\ 105 \qquad \textbf{(B)}\ 315 \qquad \textbf{(C)}\ 945 \qquad \textbf{(D)}\ 7! \qquad \textbf{(E)}\ 8!</math>
\mathrm{(A)}\  
 
\qquad
 
\mathrm{(B)}\  
 
\qquad
 
\mathrm{(C)}\  
 
\qquad
 
\mathrm{(D)}\  
 
\qquad
 
\mathrm{(E)}\  
 
</math>
 
  
 
[[2010 AMC 10B Problems/Problem 25|Solution]]
 
[[2010 AMC 10B Problems/Problem 25|Solution]]
 +
 +
==See also==
 +
{{AMC10 box|year=2010|ab=B|before=[[2010 AMC 10A Problems]]|after=[[2011 AMC 10A Problems]]}}
 +
* [[AMC 10]]
 +
* [[AMC 10 Problems and Solutions]]
 +
* [[2010 AMC 10B]]
 +
* [[Mathematics competition resources]]
 +
{{MAA Notice}}

Latest revision as of 17:33, 27 August 2024

2010 AMC 10B (Answer Key)
Printable versions: WikiAoPS ResourcesPDF

Instructions

  1. This is a 25-question, multiple choice test. Each question is followed by answers marked A, B, C, D and E. Only one of these is correct.
  2. You will receive 6 points for each correct answer, 2.5 points for each problem left unanswered if the year is before 2006, 1.5 points for each problem left unanswered if the year is after 2006, and 0 points for each incorrect answer.
  3. No aids are permitted other than scratch paper, graph paper, ruler, compass, protractor and erasers (and calculators that are accepted for use on the SAT if before 2006. No problems on the test will require the use of a calculator).
  4. Figures are not necessarily drawn to scale.
  5. You will have 75 minutes working time to complete the test.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Problem 1

What is $100(100-3)-(100\cdot100-3)$?

$\textbf{(A)}\ -20,000 \qquad \textbf{(B)}\ -10,000 \qquad \textbf{(C)}\ -297 \qquad \textbf{(D)}\ -6 \qquad \textbf{(E)}\ 0$


Solution

Problem 2

Makayla attended two meetings during her $9$-hour work day. The first meeting took $45$ minutes and the second meeting took twice as long. What percent of her work day was spent attending meetings?

$\textbf{(A)}\ 15 \qquad \textbf{(B)}\ 20 \qquad \textbf{(C)}\ 25 \qquad \textbf{(D)}\ 30 \qquad \textbf{(E)}\ 35$

Solution

Problem 3

A drawer contains red, green, blue, and white socks with at least 2 of each color. What is the minimum number of socks that must be pulled from the drawer to guarantee a matching pair?

$\textbf{(A)}\ 3 \qquad \textbf{(B)}\ 4 \qquad \textbf{(C)}\ 5 \qquad \textbf{(D)}\ 8 \qquad \textbf{(E)}\ 9$

Solution

Problem 4

For a real number $x$, define $\heartsuit(x)$ to be the average of $x$ and $x^2$. What is $\heartsuit(1)+\heartsuit(2)+\heartsuit(3)$?

$\textbf{(A)}\ 3 \qquad \textbf{(B)}\ 6 \qquad \textbf{(C)}\ 10 \qquad \textbf{(D)}\ 12 \qquad \textbf{(E)}\ 20$

Solution

Problem 5

A month with $31$ days has the same number of Mondays and Wednesdays. How many of the seven days of the week could be the first day of this month?

$\textbf{(A)}\ 2 \qquad \textbf{(B)}\ 3 \qquad \textbf{(C)}\ 4 \qquad \textbf{(D)}\ 5 \qquad \textbf{(E)}\ 6$

Solution

Problem 6

A circle is centered at $O$, $\overline{AB}$ is a diameter and $C$ is a point on the circle with $\angle COB = 50^\circ$. What is the degree measure of $\angle CAB$?

$\textbf{(A)}\ 20 \qquad \textbf{(B)}\ 25 \qquad \textbf{(C)}\ 45 \qquad \textbf{(D)}\ 50 \qquad \textbf{(E)}\ 65$

Solution

Problem 7

A triangle has side lengths $10$, $10$, and $12$. A rectangle has width $4$ and area equal to the area of the triangle. What is the perimeter of this rectangle?

$\textbf{(A)}\ 16 \qquad \textbf{(B)}\ 24 \qquad \textbf{(C)}\ 28 \qquad \textbf{(D)}\ 32 \qquad \textbf{(E)}\ 36$

Solution

Problem 8

A ticket to a school play cost $x$ dollars, where $x$ is a whole number. A group of 9th graders buys tickets costing a total of $\textdollar 48$, and a group of 10th graders buys tickets costing a total of $\textdollar 64$. How many values for $x$ are possible?

$\textbf{(A)}\ 1 \qquad \textbf{(B)}\ 2 \qquad \textbf{(C)}\ 3 \qquad \textbf{(D)}\ 4 \qquad \textbf{(E)}\ 5$

Solution

Problem 9

Lucky Larry's teacher asked him to substitute numbers for $a$, $b$, $c$, $d$, and $e$ in the expression $a-(b-(c-(d+e)))$ and evaluate the result. Larry ignored the parentheses but added and subtracted correctly and obtained the correct result by coincidence. The numbers Larry substituted for $a$, $b$, $c$, and $d$ were $1$, $2$, $3$, and $4$, respectively. What number did Larry substitute for $e$?

$\textbf{(A)}\ -5 \qquad \textbf{(B)}\ -3 \qquad \textbf{(C)}\ 0 \qquad \textbf{(D)}\ 3 \qquad \textbf{(E)}\ 5$

Solution

Problem 10

Shelby drives her scooter at a speed of $30$ miles per hour if it is not raining, and $20$ miles per hour if it is raining. Today she drove in the sun in the morning and in the rain in the evening, for a total of $16$ miles in $40$ minutes. How many minutes did she drive in the rain?

$\textbf{(A)}\ 18 \qquad \textbf{(B)}\ 21 \qquad \textbf{(C)}\ 24 \qquad \textbf{(D)}\ 27 \qquad \textbf{(E)}\ 30$

Solution

Problem 11

A shopper plans to purchase an item that has a listed price greater than $\textdollar 100$ and can use any one of the three coupons. Coupon A gives $15\%$ off the listed price, Coupon B gives $\textdollar 30$ off the listed price, and Coupon C gives $25\%$ off the amount by which the listed price exceeds $\textdollar 100$.
Let $x$ and $y$ be the smallest and largest prices, respectively, for which Coupon A saves at least as many dollars as Coupon B or Coupon C. What is $y - x$?

$\textbf{(A)}\ 50 \qquad \textbf{(B)}\ 60 \qquad \textbf{(C)}\ 75 \qquad \textbf{(D)}\ 80  \qquad \textbf{(E)}\ 100$

Solution

Problem 12

At the beginning of the school year, $50\%$ of all students in Mr. Wells' math class answered "Yes" to the question "Do you love math", and $50\%$ answered "No." At the end of the school year, $70\%$ answered "Yes" and $30\%$ answered "No." Altogether, $x\%$ of the students gave a different answer at the beginning and end of the school year. What is the difference between the maximum and the minimum possible values of $x$?

$\textbf{(A)}\ 0 \qquad \textbf{(B)}\ 20 \qquad \textbf{(C)}\ 40 \qquad \textbf{(D)}\ 60 \qquad \textbf{(E)}\ 80$

Solution

Problem 13

What is the sum of all the solutions of $x = \left|2x-|60-2x|\right|$?

$\textbf{(A)}\ 32 \qquad \textbf{(B)}\ 60 \qquad \textbf{(C)}\ 92 \qquad \textbf{(D)}\ 120 \qquad \textbf{(E)}\ 124$

Solution

Problem 14

The average of the numbers $1, 2, 3,\cdots, 98, 99,$ and $x$ is $100x$. What is $x$?

$\textbf{(A)}\ \dfrac{49}{101} \qquad \textbf{(B)}\ \dfrac{50}{101} \qquad \textbf{(C)}\ \dfrac{1}{2} \qquad \textbf{(D)}\ \dfrac{51}{101} \qquad \textbf{(E)}\ \dfrac{50}{99}$

Solution

Problem 15

On a $50$-question multiple choice math contest, students receive $4$ points for a correct answer, $0$ points for an answer left blank, and $-1$ point for an incorrect answer. Jesse’s total score on the contest was $99$. What is the maximum number of questions that Jesse could have answered correctly?

$\textbf{(A)}\ 25 \qquad \textbf{(B)}\ 27 \qquad \textbf{(C)}\ 29 \qquad \textbf{(D)}\ 31 \qquad \textbf{(E)}\ 33$

Solution

Problem 16

A square of side length $1$ and a circle of radius $\dfrac{\sqrt{3}}{3}$ share the same center. What is the area inside the circle, but outside the square?

$\textbf{(A)}\ \dfrac{\pi}{3}-1 \qquad \textbf{(B)}\ \dfrac{2\pi}{9}-\dfrac{\sqrt{3}}{3} \qquad \textbf{(C)}\ \dfrac{\pi}{18} \qquad \textbf{(D)}\ \dfrac{1}{4} \qquad \textbf{(E)}\ \dfrac{2\pi}{9}$

Solution

Problem 17

Every high school in the city of Euclid sent a team of $3$ students to a math contest. Each participant in the contest received a different score. Andrea's score was the median among all students, and hers was the highest score on her team. Andrea's teammates Beth and Carla placed $37$th and $64$th, respectively. How many schools are in the city?

$\textbf{(A)}\ 22 \qquad \textbf{(B)}\ 23 \qquad \textbf{(C)}\ 24 \qquad \textbf{(D)}\ 25 \qquad \textbf{(E)}\ 26$

Solution

Problem 18

Positive integers $a$, $b$, and $c$ are randomly and independently selected with replacement from the set $\{1, 2, 3,\dots, 2010\}$. What is the probability that $abc + ab + a$ is divisible by $3$?

$\textbf{(A)}\ \dfrac{1}{3} \qquad \textbf{(B)}\ \dfrac{29}{81} \qquad \textbf{(C)}\ \dfrac{31}{81} \qquad \textbf{(D)}\ \dfrac{11}{27} \qquad \textbf{(E)}\ \dfrac{13}{27}$

Solution

Problem 19

A circle with center $O$ has area $156\pi$. Triangle $ABC$ is equilateral, $\overline{BC}$ is a chord on the circle, $OA = 4\sqrt{3}$, and point $O$ is outside $\triangle ABC$. What is the side length of $\triangle ABC$?

$\textbf{(A)}\ 2\sqrt{3} \qquad \textbf{(B)}\ 6 \qquad \textbf{(C)}\ 4\sqrt{3} \qquad \textbf{(D)}\ 12 \qquad \textbf{(E)}\ 18$

Solution

Problem 20

Two circles lie outside regular hexagon $ABCDEF$. The first is tangent to $\overline{AB}$, and the second is tangent to $\overline{DE}$. Both are tangent to lines $BC$ and $FA$. What is the ratio of the area of the second circle to that of the first circle?

$\textbf{(A)}\ 18 \qquad \textbf{(B)}\ 27 \qquad \textbf{(C)}\ 36 \qquad \textbf{(D)}\ 81 \qquad \textbf{(E)}\ 108$

Solution

Problem 21

A palindrome between $1000$ and $10,000$ is chosen at random. What is the probability that it is divisible by $7$?

$\textbf{(A)}\ \dfrac{1}{10} \qquad \textbf{(B)}\ \dfrac{1}{9} \qquad \textbf{(C)}\ \dfrac{1}{7} \qquad \textbf{(D)}\ \dfrac{1}{6} \qquad \textbf{(E)}\ \dfrac{1}{5}$

Solution

Problem 22

Seven distinct pieces of candy are to be distributed among three bags. The red bag and the blue bag must each receive at least one piece of candy; the white bag may remain empty. How many arrangements are possible?

$\textbf{(A)}\ 1930 \qquad \textbf{(B)}\ 1931 \qquad \textbf{(C)}\ 1932 \qquad \textbf{(D)}\ 1933 \qquad \textbf{(E)}\ 1934$

Solution

Problem 23

The entries in a $3 \times 3$ array include all the digits from $1$ through $9$, arranged so that the entries in every row and column are in increasing order. How many such arrays are there?

$\textbf{(A)}\ 18 \qquad \textbf{(B)}\ 24 \qquad \textbf{(C)}\ 36 \qquad \textbf{(D)}\ 42 \qquad \textbf{(E)}\ 60$

Solution

Problem 24

A high school basketball game between the Raiders and Wildcats was tied at the end of the first quarter. The number of points scored by the Raiders in each of the four quarters formed an increasing geometric sequence, and the number of points scored by the Wildcats in each of the four quarters formed an increasing arithmetic sequence. At the end of the fourth quarter, the Raiders had won by one point. Neither team scored more than $100$ points. What was the total number of points scored by the two teams in the first half?

$\textbf{(A)}\ 30 \qquad \textbf{(B)}\ 31 \qquad \textbf{(C)}\ 32 \qquad \textbf{(D)}\ 33 \qquad \textbf{(E)}\ 34$

Solution

Problem 25

Let $a > 0$, and let $P(x)$ be a polynomial with integer coefficients such that

$P(1) = P(3) = P(5) = P(7) = a$, and
$P(2) = P(4) = P(6) = P(8) = -a$.

What is the smallest possible value of $a$?

$\textbf{(A)}\ 105 \qquad \textbf{(B)}\ 315 \qquad \textbf{(C)}\ 945 \qquad \textbf{(D)}\ 7! \qquad \textbf{(E)}\ 8!$

Solution

See also

2010 AMC 10B (ProblemsAnswer KeyResources)
Preceded by
2010 AMC 10A Problems
Followed by
2011 AMC 10A Problems
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All AMC 10 Problems and Solutions

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