Difference between revisions of "2007 AMC 10B Problems"
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+ | {{AMC10 Problems|year=2007|ab=B}} | ||
==Problem 1== | ==Problem 1== | ||
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\textbf{(C) } \text{All Arogs are Crups and are Dramps.}\\ | \textbf{(C) } \text{All Arogs are Crups and are Dramps.}\\ | ||
\textbf{(D) } \text{All Crups are Arogs and are Brafs.}\\ | \textbf{(D) } \text{All Crups are Arogs and are Brafs.}\\ | ||
− | \textbf{(E) } \text{All Arogs are Dramps and some Arogs may not be | + | \textbf{(E) } \text{All Arogs are Dramps and some Arogs may not be Crups.}</math> |
[[2007 AMC 10B Problems/Problem 5|Solution]] | [[2007 AMC 10B Problems/Problem 5|Solution]] | ||
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==Problem 6== | ==Problem 6== | ||
− | The 2007 | + | The <math>2007</math> <math>\text{AMC}</math> <math>10</math> will be scored by awarding <math>6</math> points for each correct response, <math>0</math> points for each incorrect response, and <math>1.5</math> points for each problem left unanswered. After looking over the <math>25</math> problems, Sarah has decided to attempt the first <math>22</math> and leave only the last <math>3</math> unanswered. How many of the first <math>22</math> problems must she solve correctly in order to score at least <math>100</math> points? |
<math>\textbf{(A) } 13 \qquad\textbf{(B) } 14 \qquad\textbf{(C) } 15 \qquad\textbf{(D) } 16 \qquad\textbf{(E) } 17</math> | <math>\textbf{(A) } 13 \qquad\textbf{(B) } 14 \qquad\textbf{(C) } 15 \qquad\textbf{(D) } 16 \qquad\textbf{(E) } 17</math> | ||
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Right <math>\triangle ABC</math> has <math>AB=3, BC=4,</math> and <math>AC=5.</math> Square <math>XYZW</math> is inscribed in <math>\triangle ABC</math> with <math>X</math> and <math>Y</math> on <math>\overline{AC}, W</math> on <math>\overline{AB},</math> and <math>Z</math> on <math>\overline{BC}.</math> What is the side length of the square? | Right <math>\triangle ABC</math> has <math>AB=3, BC=4,</math> and <math>AC=5.</math> Square <math>XYZW</math> is inscribed in <math>\triangle ABC</math> with <math>X</math> and <math>Y</math> on <math>\overline{AC}, W</math> on <math>\overline{AB},</math> and <math>Z</math> on <math>\overline{BC}.</math> What is the side length of the square? | ||
− | <math>\textbf{(A) } \frac{3}{2} \qquad\textbf{(B) } \frac{60}{37} \qquad\textbf{(C) } \frac{12}{7} \qquad\textbf{(D) } \frac{23}{13} \qquad\ | + | <math>\textbf{(A) } \frac{3}{2} \qquad\textbf{(B) } \frac{60}{37} \qquad\textbf{(C) } \frac{12}{7} \qquad\textbf{(D) } \frac{23}{13} \qquad\text{(E) 2} </math> |
[[2007 AMC 10B Problems/Problem 21|Solution]] | [[2007 AMC 10B Problems/Problem 21|Solution]] |
Latest revision as of 12:57, 19 February 2020
2007 AMC 10B (Answer Key) Printable versions: • AoPS Resources • PDF | ||
Instructions
| ||
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 |
Contents
- 1 Problem 1
- 2 Problem 2
- 3 Problem 3
- 4 Problem 4
- 5 Problem 5
- 6 Problem 6
- 7 Problem 7
- 8 Problem 8
- 9 Problem 9
- 10 Problem 10
- 11 Problem 11
- 12 Problem 12
- 13 Problem 13
- 14 Problem 14
- 15 Problem 15
- 16 Problem 16
- 17 Problem 17
- 18 Problem 18
- 19 Problem 19
- 20 Problem 20
- 21 Problem 21
- 22 Problem 22
- 23 Problem 23
- 24 Problem 24
- 25 Problem 25
- 26 See also
Problem 1
Isabella's house has bedrooms. Each bedroom is
feet long,
feet wide, and
feet high. Isabella must paint the walls of all the bedrooms. Doorways and windows, which will not be painted, occupy
square feet in each bedroom. How many square feet of walls must be painted?
Problem 2
Define the operation by
What is
Problem 3
A college student drove his compact car miles home for the weekend and averaged
miles per gallon. On the return trip the student drove his parents' SUV and averaged only
miles per gallon. What was the average gas mileage, in miles per gallon, for the round trip?
Problem 4
The point is the center of the circle circumscribed about
with
and
. What is the degree measure of
Problem 5
In a certain land, all Arogs are Brafs, all Crups are Brafs, all Dramps are Arogs, and all Crups are Dramps. Which of the following statements is implied by these facts?
Problem 6
The
will be scored by awarding
points for each correct response,
points for each incorrect response, and
points for each problem left unanswered. After looking over the
problems, Sarah has decided to attempt the first
and leave only the last
unanswered. How many of the first
problems must she solve correctly in order to score at least
points?
Problem 7
All sides of the convex pentagon are of equal length, and
What is the degree measure of
Problem 8
On the trip home from the meeting where this AMC10 was constructed, the Contest Chair noted that his airport parking receipt had digits of the form where
and
was the average of
and
How many different five-digit numbers satisfy all these properties?
Problem 9
A cryptographic code is designed as follows. The first time a letter appears in a given message it is replaced by the letter that is place to its right in the alphabet (assuming that the letter
is one place to the right of the letter
). The second time this same letter appears in the given message, it is replaced by the letter that is
places to the right, the third time it is replaced by the letter that is
places to the right, and so on. For example, with this code the word "banana" becomes "cbodqg". What letter will replace the last letter
in the message
Problem 10
Two points and
are in a plane. Let
be the set of all points
in the plane for which
has area
Which of the following describes
Problem 11
A circle passes through the three vertices of an isosceles triangle that has two sides of length and a base of length
What is the area of this circle?
Problem 12
Tom's age is years, which is also the sum of the ages of his three children. His age
years ago was twice the sum of their ages then. What is
Problem 13
Two circles of radius are centered at
and at
What is the area of the intersection of the interiors of the two circles?
Problem 14
Some boys and girls are having a car wash to raise money for a class trip to China. Initially of the group are girls. Shortly thereafter two girls leave and two boys arrive, and then
of the group are girls. How many girls were initially in the group?
Problem 15
The angles of quadrilateral satisfy
What is the degree measure of
rounded to the nearest whole number?
Problem 16
A teacher gave a test to a class in which of the students are juniors and
are seniors. The average score on the test was
The juniors all received the same score, and the average score of the seniors was
What score did each of the juniors receive on the test?
Problem 17
Point is inside equilateral
Points
and
are the feet of the perpendiculars from
to
and
respectively. Given that
and
what is
Problem 18
A circle of radius is surrounded by
circles of radius
as shown. What is
?
![[asy] unitsize(3mm); defaultpen(linewidth(.8pt)+fontsize(7pt)); dotfactor=4; real r1=1, r2=1+sqrt(2); pair A=(0,0), B=(1+sqrt(2),1+sqrt(2)), C=(-1-sqrt(2),1+sqrt(2)), D=(-1-sqrt(2),-1-sqrt(2)), E=(1+sqrt(2),-1-sqrt(2)); pair A1=(1,0), B1=(2+2sqrt(2),1+sqrt(2)), C1=(0,1+sqrt(2)), D1=(0,-1-sqrt(2)), E1=(2+2sqrt(2),-1-sqrt(2)); path circleA=Circle(A,r1); path circleB=Circle(B,r2); path circleC=Circle(C,r2); path circleD=Circle(D,r2); path circleE=Circle(E,r2); draw(circleA); draw(circleB); draw(circleC); draw(circleD); draw(circleE); draw(A--A1); draw(B--B1); draw(C--C1); draw(D--D1); draw(E--E1); label("$1$",midpoint(A--A1),N); label("$r$",midpoint(B--B1),N); label("$r$",midpoint(C--C1),N); label("$r$",midpoint(D--D1),N); label("$r$",midpoint(E--E1),N); [/asy]](http://latex.artofproblemsolving.com/6/b/8/6b83570902439de3661af1cf5b186d453fed927f.png)
Problem 19
The wheel shown is spun twice, and the randomly determined numbers opposite the pointer are recorded. The first number is divided by and the second number is divided by
The first remainder designates a column, and the second remainder designates a row on the checkerboard shown. What is the probability that the pair of numbers designates a shaded square?
![[asy] unitsize(5mm); defaultpen(linewidth(.8pt)+fontsize(10pt)); dotfactor=4; real r=2; pair O=(0,0); pair A=(0,2), A1=(0,-2); draw(A--A1); pair B=(sqrt(3),1), B1=(-sqrt(3),-1); draw(B--B1); pair C=(sqrt(3),-1), C1=(-sqrt(3),1); draw(C--C1); path circleO=Circle(O,r); draw(circleO); pair[] ps={O}; dot(ps); label("$6$",(-0.6,1)); label("$1$",(0.6,1)); label("$2$",(0.6,-1)); label("$9$",(-0.6,-1)); label("$7$",(1.2,0)); label("$3$",(-1.2,0)); label("$pointer$",(-4,0)); draw((-5.5,0.5)--(-5.5,-0.5)--(-3,-0.5)--(-2.5,0)--(-3,0.5)--cycle); fill((4,0)--(4,1)--(5,1)--(5,0)--cycle,gray); fill((6,2)--(6,1)--(5,1)--(5,2)--cycle,gray); fill((6,0)--(6,-1)--(5,-1)--(5,0)--cycle,gray); fill((6,0)--(6,1)--(7,1)--(7,0)--cycle,gray); fill((4,-1)--(5,-1)--(5,-2)--(4,-2)--cycle,gray); fill((6,-1)--(7,-1)--(7,-2)--(6,-2)--cycle,gray); draw((4,2)--(7,2)--(7,-2)--(4,-2)--cycle); draw((4,1)--(7,1)); draw((4,0)--(7,0)); draw((4,-1)--(7,-1)); draw((5,2)--(5,-2)); draw((6,2)--(6,-2)); label("$1$",midpoint((4,-1)--(4,-2)),W); label("$2$",midpoint((4,0)--(4,-1)),W); label("$3$",midpoint((4,1)--(4,0)),W); label("$4$",midpoint((4,2)--(4,1)),W); label("$1$",midpoint((4,-2)--(5,-2)),S); label("$2$",midpoint((5,-2)--(6,-2)),S); label("$3$",midpoint((7,-2)--(6,-2)),S); [/asy]](http://latex.artofproblemsolving.com/d/1/6/d16f5082e7ba12a9e32d1bd5aad7b6620c1985ae.png)
Problem 20
A set of square blocks is arranged into a
square. How many different combinations of
blocks can be selected from that set so that no two are in the same row or column?
Problem 21
Right has
and
Square
is inscribed in
with
and
on
on
and
on
What is the side length of the square?
Problem 22
A player chooses one of the numbers through
. After the choice has been made, two regular four-sided (tetrahedral) dice are rolled, with the sides of the dice numbered
through
If the number chosen appears on the bottom of exactly one die after it has been rolled, then the player wins
dollar. If the number chosen appears on the bottom of both of the dice, then the player wins
dollars. If the number chosen does not appear on the bottom of either of the dice, the player loses
dollar. What is the expected return to the player, in dollars, for one roll of the dice?
Problem 23
A pyramid with a square base is cut by a plane that is parallel to its base and units from the base. The surface area of the smaller pyramid that is cut from the top is half the surface area of the original pyramid. What is the altitude of the original pyramid?
Problem 24
Let denote the smallest positive integer that is divisible by both
and
and whose base-
representation consists of only
's and
's, with at least one of each. What are the last four digits of
Problem 25
How many pairs of positive integers are there such that
and
have no common factors greater than
and
is an integer?
See also
2007 AMC 10B (Problems • Answer Key • Resources) | ||
Preceded by 2007 AMC 10A Problems |
Followed by 2008 AMC 10A Problems | |
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 | ||
All AMC 10 Problems and Solutions |
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.