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Difference between revisions of "1988 AJHSME Problems"
m (Same change made to the individual problem)
 
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{{AJHSME Problems
 +
|year = 1988
 +
}}
 
== Problem 1 ==
 
== Problem 1 ==
  
Line 36: Line 39:
  
 
== Problem 4 ==
 
== Problem 4 ==
 +
 +
The figure consists of alternating light and dark squares.  The number of dark squares exceeds the number of light squares by
 +
 +
<math>\text{(A)}\ 7 \qquad \text{(B)}\ 8 \qquad \text{(C)}\ 9 \qquad \text{(D)}\ 10 \qquad \text{(E)}\ 11</math>
 +
 +
<asy>
 +
unitsize(12);
 +
//Force a white background in middle even when transparent
 +
fill((3,1)--(12,1)--(12,4)--(3,4)--cycle,white);
 +
//Black Squares, Gray Border (blends better than white)
 +
for(int a=0; a<7; ++a)
 +
{
 +
  filldraw((2a,0)--(2a+1,0)--(2a+1,1)--(2a,1)--cycle,black,gray);
 +
}
 +
for(int b=7; b<15; ++b)
 +
{
 +
  filldraw((b,14-b)--(b+1,14-b)--(b+1,15-b)--(b,15-b)--cycle,black,gray);
 +
}
 +
for(int c=1; c<7; ++c)
 +
{
 +
  filldraw((c,c)--(c+1,c)--(c+1,c+1)--(c,c+1)--cycle,black,gray);
 +
}
 +
filldraw((6,4)--(7,4)--(7,5)--(6,5)--cycle,black,gray);
 +
filldraw((7,5)--(8,5)--(8,6)--(7,6)--cycle,black,gray);
 +
filldraw((8,4)--(9,4)--(9,5)--(8,5)--cycle,black,gray);
 +
//White Squares, Black Border
 +
filldraw((7,4)--(8,4)--(8,5)--(7,5)--cycle,white,black);
 +
for(int a=0; a<7; ++a)
 +
{
 +
  filldraw((2a+1,0)--(2a+2,0)--(2a+2,1)--(2a+1,1)--cycle,white,black);
 +
}
 +
for(int b=9; b<15; ++b)
 +
{
 +
  filldraw((b-1,14-b)--(b,14-b)--(b,15-b)--(b-1,15-b)--cycle,white,black);
 +
}
 +
for(int c=1; c<7; ++c)
 +
{
 +
  filldraw((c+1,c)--(c+2,c)--(c+2,c+1)--(c+1,c+1)--cycle,white,black);
 +
}
 +
label("same",(6.3,2.45),N);
 +
label("pattern here",(7.5,1.4),N);
 +
</asy>
  
 
[[1988 AJHSME Problems/Problem 4|Solution]]
 
[[1988 AJHSME Problems/Problem 4|Solution]]
  
 
== Problem 5 ==
 
== Problem 5 ==
 +
 +
If <math>\angle \text{CBD}</math> is a right angle, then this protractor indicates that the measure of <math>\angle \text{ABC}</math> is approximately
 +
 +
<asy>
 +
unitsize(36);
 +
pair A,B,C,D;
 +
A=3*dir(160); B=origin; C=3*dir(110); D=3*dir(20);
 +
draw((1.5,0)..(0,1.5)..(-1.5,0));
 +
draw((2.5,0)..(0,2.5)..(-2.5,0)--cycle);
 +
draw(A--B); draw(C--B); draw(D--B);
 +
label("O",(-2.5,0),W);
 +
label("A",A,W);
 +
label("B",B,S);
 +
label("C",C,W);
 +
label("D",D,E);
 +
label("0",(-1.8,0),W);
 +
label("20",(-1.7,.5),NW);
 +
label("160",(1.6,.5),NE);
 +
label("180",(1.7,0),E);
 +
</asy>
 +
 +
<math>\text{(A)}\ 20^\circ \qquad \text{(B)}\ 40^\circ \qquad \text{(C)}\ 50^\circ \qquad \text{(D)}\ 70^\circ \qquad \text{(E)}\ 120^\circ</math>
  
 
[[1988 AJHSME Problems/Problem 5|Solution]]
 
[[1988 AJHSME Problems/Problem 5|Solution]]
Line 68: Line 135:
  
 
== Problem 9 ==
 
== Problem 9 ==
 +
 +
An isosceles triangle is a triangle with two sides of equal length.  How many of the five triangles on the square grid below are isosceles?
 +
 +
<asy>
 +
for(int a=0; a<12; ++a)
 +
{
 +
  draw((a,0)--(a,6));
 +
}
 +
for(int b=0; b<7; ++b)
 +
{
 +
  draw((0,b)--(11,b));
 +
}
 +
draw((0,6)--(2,6)--(1,4)--cycle,linewidth(1));
 +
draw((3,4)--(3,6)--(5,4)--cycle,linewidth(1));
 +
draw((0,1)--(3,2)--(6,1)--cycle,linewidth(1));
 +
draw((7,4)--(6,6)--(9,4)--cycle,linewidth(1));
 +
draw((8,1)--(9,3)--(10,0)--cycle,linewidth(1));
 +
</asy>
 +
 +
<math>\text{(A)}\ 1 \qquad \text{(B)}\ 2 \qquad \text{(C)}\ 3 \qquad \text{(D)}\ 4 \qquad \text{(E)}\ 5</math>
  
 
[[1988 AJHSME Problems/Problem 9|Solution]]
 
[[1988 AJHSME Problems/Problem 9|Solution]]
Line 73: Line 160:
 
== Problem 10 ==
 
== Problem 10 ==
  
−
Chris' birthday is on a Thursday this year.  What day of the week will it be <math>60</math> days after her birthday?
+
Chris's birthday is on a Thursday this year.  What day of the week will it be <math>60</math> days after her birthday?
  
 
<math>\text{(A)}\ \text{Monday} \qquad \text{(B)}\ \text{Wednesday} \qquad \text{(C)}\ \text{Thursday} \qquad \text{(D)}\ \text{Friday} \qquad \text{(E)}\ \text{Saturday}</math>
 
<math>\text{(A)}\ \text{Monday} \qquad \text{(B)}\ \text{Wednesday} \qquad \text{(C)}\ \text{Thursday} \qquad \text{(D)}\ \text{Friday} \qquad \text{(E)}\ \text{Saturday}</math>
Line 91: Line 178:
 
Suppose the estimated <math>20</math> billion dollar cost to send a person to the planet Mars is shared equally by the <math>250</math> million people in the U.S. Then each person's share is  
 
Suppose the estimated <math>20</math> billion dollar cost to send a person to the planet Mars is shared equally by the <math>250</math> million people in the U.S. Then each person's share is  
  
−
<math>\text{(A)}\ 40\text{ dollars} \qquad \text{(B)}\ 50\text{ dollars} \qquad \text{(C)}\ 80\text{ dollars} \qquad \text{(D)}\ 100\text{ dollars} \qquad \text{(E)}\ 125\text{ dollars}</math>
+
<math>\text{(A)}\ 20\text{ dollars} \qquad \text{(B)}\ 50\text{ dollars} \qquad \text{(C)}\ 80\text{ dollars} \qquad \text{(D)}\ 100\text{ dollars} \qquad \text{(E)}\ 125\text{ dollars}</math>
  
 
[[1988 AJHSME Problems/Problem 12|Solution]]
 
[[1988 AJHSME Problems/Problem 12|Solution]]
Line 120: Line 207:
  
 
== Problem 16 ==
 
== Problem 16 ==
 +
 +
Placing no more than one <math>\text{X}</math> in each small square, what is the greatest number of <math>\text{X}</math>'s that can be put on the grid shown without getting three <math>\text{X}</math>'s in a row vertically, horizontally, or diagonally?
 +
 +
<math>\text{(A)}\ 2 \qquad \text{(B)}\ 3 \qquad \text{(C)}\ 4 \qquad \text{(D)}\ 5 \qquad \text{(E)}\ 6</math>
 +
 +
<asy>
 +
for(int a=0; a<4; ++a)
 +
{
 +
  draw((a,0)--(a,3));
 +
}
 +
for(int b=0; b<4; ++b)
 +
{
 +
  draw((0,b)--(3,b));
 +
}
 +
</asy>
  
 
[[1988 AJHSME Problems/Problem 16|Solution]]
 
[[1988 AJHSME Problems/Problem 16|Solution]]
  
 
== Problem 17 ==
 
== Problem 17 ==
 +
 +
The shaded region formed by the two intersecting perpendicular rectangles, in square units, is
 +
 +
<asy>
 +
fill((0,0)--(6,0)--(6,-3.5)--(9,-3.5)--(9,0)--(10,0)--(10,2)--(9,2)--(9,4.5)--(6,4.5)--(6,2)--(0,2)--cycle,black);
 +
label("2",(0,.9),W);
 +
label("3",(7.3,4.5),N);
 +
draw((0,-3.3)--(0,-5.3),linewidth(1));
 +
draw((0,-4.3)--(3.7,-4.3),linewidth(1));
 +
label("10",(4.7,-3.7),S);
 +
draw((5.7,-4.3)--(10,-4.3),linewidth(1));
 +
draw((10,-3.3)--(10,-5.3),linewidth(1));
 +
draw((11,4.5)--(13,4.5),linewidth(1));
 +
draw((12,4.5)--(12,2),linewidth(1));
 +
label("8",(11.3,1),E);
 +
draw((12,0)--(12,-3.5),linewidth(1));
 +
draw((11,-3.5)--(13,-3.5),linewidth(1));
 +
</asy>
 +
 +
<math>\text{(A)}\ 23 \qquad \text{(B)}\ 38 \qquad \text{(C)}\ 44 \qquad \text{(D)}\ 46 \qquad \text{(E)}\ \text{unable to be determined from the information given}</math>
  
 
[[1988 AJHSME Problems/Problem 17|Solution]]
 
[[1988 AJHSME Problems/Problem 17|Solution]]
  
 
== Problem 18 ==
 
== Problem 18 ==
 +
 +
The average weight of <math>6</math> boys is <math>150</math> pounds and the average weight of <math>4</math> girls is <math>120</math> pounds.  The average weight of the <math>10</math> children is
 +
 +
<math>\text{(A)}\ 135\text{ pounds} \qquad \text{(B)}\ 137\text{ pounds} \qquad \text{(C)}\ 138\text{ pounds} \qquad \text{(D)}\ 140\text{ pounds} \qquad \text{(E)}\ 141\text{ pounds}</math>
  
 
[[1988 AJHSME Problems/Problem 18|Solution]]
 
[[1988 AJHSME Problems/Problem 18|Solution]]
  
 
== Problem 19 ==
 
== Problem 19 ==
 +
 +
What is the <math>100\text{th}</math> number in the arithmetic sequence: <math>1,5,9,13,17,21,25,...</math>?
 +
 +
<math>\text{(A)}\ 397 \qquad \text{(B)}\ 399 \qquad \text{(C)}\ 401 \qquad \text{(D)}\ 403 \qquad \text{(E)}\ 405</math>
  
 
[[1988 AJHSME Problems/Problem 19|Solution]]
 
[[1988 AJHSME Problems/Problem 19|Solution]]
  
 
== Problem 20 ==
 
== Problem 20 ==
 +
 +
The glass gauge on a cylindrical coffee maker shows that there are <math>45</math> cups left when the coffee maker is <math>36\% </math> full.  How many cups of coffee does it hold when it is full?
 +
 +
<math>\text{(A)}\ 80 \qquad \text{(B)}\ 100 \qquad \text{(C)}\ 125 \qquad \text{(D)}\ 130 \qquad \text{(E)}\ 262</math>
 +
 +
<asy>
 +
draw((5,0)..(0,-1.3)..(-5,0));
 +
draw((5,0)--(5,10)); draw((-5,0)--(-5,10));
 +
draw(ellipse((0,10),5,1.3));
 +
draw(circle((.3,1.3),.4));
 +
draw((-.1,1.7)--(-.1,7.9)--(.7,7.9)--(.7,1.7)--cycle);
 +
fill((-.1,1.7)--(-.1,4)--(.7,4)--(.7,1.7)--cycle,black);
 +
draw((-2,11.3)--(2,11.3)..(2.6,11.9)..(2,12.2)--(-2,12.2)..(-2.6,11.9)..cycle);
 +
</asy>
  
 
[[1988 AJHSME Problems/Problem 20|Solution]]
 
[[1988 AJHSME Problems/Problem 20|Solution]]
  
 
== Problem 21 ==
 
== Problem 21 ==
 +
 +
A fifth number, <math>n</math>, is added to the set <math>\{ 3,6,9,10 \}</math> to make the mean of the set of five numbers equal to its median.  The number of possible values of <math>n</math> is
 +
 +
<math>\text{(A)}\ 1 \qquad \text{(B)}\ 2 \qquad \text{(C)}\ 3 \qquad \text{(D)}\ 4 \qquad \text{(E)}\ \text{more than }4</math>
  
 
[[1988 AJHSME Problems/Problem 21|Solution]]
 
[[1988 AJHSME Problems/Problem 21|Solution]]
  
 
== Problem 22 ==
 
== Problem 22 ==
 +
 +
Tom's Hat Shoppe increased all original prices by <math>25\% </math>.  Now the shoppe is having a sale where all prices are <math>20\% </math> off these increased prices.  Which statement best describes the sale price of an item?
 +
 +
<math>\text{(A)}\ \text{The sale price is }5\% \text{ higher than the original price.}</math>
 +
 +
<math>\text{(B)}\ \text{The sale price is higher than the original price, but by less than }5\% .</math>
 +
 +
<math>\text{(C)}\ \text{The sale price is higher than the original price, but by more than }5\% .</math>
 +
 +
<math>\text{(D)}\ \text{The sale price is lower than the original price.}</math>
 +
 +
<math>\text{(E)}\ \text{The sale price is the same as the original price.}</math>
  
 
[[1988 AJHSME Problems/Problem 22|Solution]]
 
[[1988 AJHSME Problems/Problem 22|Solution]]
  
 
== Problem 23 ==
 
== Problem 23 ==
 +
 +
Maria buys computer disks at a price of <math>4</math> for <math><dollar>5</math> and sells them at a price of <math>3</math> for <math><dollar></math><math>5</math>.  How many computer disks must she sell in order to make a profit of <math><dollar>100</math>?
 +
 +
<math>\text{(A)}\ 100 \qquad \text{(B)}\ 120 \qquad \text{(C)}\ 200 \qquad \text{(D)}\ 240 \qquad \text{(E)}\ 1200</math>
  
 
[[1988 AJHSME Problems/Problem 23|Solution]]
 
[[1988 AJHSME Problems/Problem 23|Solution]]
  
 
== Problem 24 ==
 
== Problem 24 ==
 +
 +
<asy>
 +
unitsize(15);
 +
for (int a=0; a<6; ++a)
 +
{
 +
  draw(2*dir(60a)--2*dir(60a+60),linewidth(1));
 +
}
 +
draw((1,1.7320508075688772935274463415059)--(1,3.7320508075688772935274463415059)--(-1,3.7320508075688772935274463415059)--(-1,1.7320508075688772935274463415059)--cycle,linewidth(1));
 +
fill((.4,1.7320508075688772935274463415059)--(0,3.35)--(-.4,1.7320508075688772935274463415059)--cycle,black);
 +
label("1.",(0,-2),S);
 +
draw(arc((1,1.7320508075688772935274463415059),1,90,300,CW));
 +
draw((1.5,0.86602540378443864676372317075294)--(1.75,1.7));
 +
draw((1.5,0.86602540378443864676372317075294)--(2.2,1));
 +
draw((7,0)--(6,1.7320508075688772935274463415059)--(4,1.7320508075688772935274463415059)--(3,0)--(4,-1.7320508075688772935274463415059)--(6,-1.7320508075688772935274463415059)--cycle,linewidth(1));
 +
draw((7,0)--(6,1.7320508075688772935274463415059)--(7.7320508075688772935274463415059,2.7320508075688772935274463415059)--(8.7320508075688772935274463415059,1)--cycle,linewidth(1));
 +
label("2.",(5,-2),S);
 +
draw(arc((7,0),1,30,240,CW));
 +
draw((6.5,-0.86602540378443864676372317075294)--(7.1,-.7));
 +
draw((6.5,-0.86602540378443864676372317075294)--(6.8,-1.5));
 +
draw((14,0)--(13,1.7320508075688772935274463415059)--(11,1.7320508075688772935274463415059)--(10,0)--(11,-1.7320508075688772935274463415059)--(13,-1.7320508075688772935274463415059)--cycle,linewidth(1));
 +
draw((14,0)--(13,-1.7320508075688772935274463415059)--(14.7320508075688772935274463415059,-2.7320508075688772935274463415059)--(15.7320508075688772935274463415059,-1)--cycle,linewidth(1));
 +
label("3.",(12,-2.5),S);
 +
draw((21,0)--(20,1.7320508075688772935274463415059)--(18,1.7320508075688772935274463415059)--(17,0)--(18,-1.7320508075688772935274463415059)--(20,-1.7320508075688772935274463415059)--cycle,linewidth(1));
 +
draw((18,-1.7320508075688772935274463415059)--(20,-1.7320508075688772935274463415059)--(20,-3.7320508075688772935274463415059)--(18,-3.7320508075688772935274463415059)--cycle,linewidth(1));
 +
label("4.",(19,-4),S);
 +
</asy>
 +
 +
The square in the first diagram "rolls" clockwise around the fixed regular hexagon until it reaches the bottom.  In which position will the solid triangle be in diagram <math>4</math>?
 +
 +
<asy>
 +
unitsize(12);
 +
label("(A)",(0,0),W);
 +
fill((1,-1)--(1,1)--(5,0)--cycle,black);
 +
label("(B)",(6,0),E);
 +
fill((9,-2)--(11,-2)--(10,1)--cycle,black);
 +
label("(C)",(14,0),E);
 +
fill((17,1)--(19,1)--(18,-1.8)--cycle,black);
 +
label("(D)",(22,0),E);
 +
fill((25,-1)--(27,-2)--(28,1)--cycle,black);
 +
label("(E)",(31,0),E);
 +
fill((33,0)--(37,1)--(37,-1)--cycle,black);
 +
</asy>
  
 
[[1988 AJHSME Problems/Problem 24|Solution]]
 
[[1988 AJHSME Problems/Problem 24|Solution]]
  
 
== Problem 25 ==
 
== Problem 25 ==
 +
 +
A '''palindrome''' is a whole number that reads the same forwards and backwards.  If one neglects the colon, certain times displayed on a digital watch are palindromes.  Three examples are: <math>\boxed{1:01}</math>, <math>\boxed{4:44}</math>, and <math>\boxed{12:21}</math>.  How many times during a <math>12</math>-hour period will be palindromes?
 +
 +
<math>\text{(A)}\ 57 \qquad \text{(B)}\ 60 \qquad \text{(C)}\ 63 \qquad \text{(D)}\ 90 \qquad \text{(E)}\ 93</math>
  
 
[[1988 AJHSME Problems/Problem 25|Solution]]
 
[[1988 AJHSME Problems/Problem 25|Solution]]
  
 
== See also ==
 
== See also ==
 +
{{AJHSME box|year=1988|before=[[1987 AJHSME Problems|1987 AJHSME]]|after=[[1989 AJHSME Problems|1989 AJHSME]]}}
 
* [[AJHSME]]
 
* [[AJHSME]]
 
* [[AJHSME Problems and Solutions]]
 
* [[AJHSME Problems and Solutions]]
−
* [[1988 AJHSME]]
 
 
* [[Mathematics competition resources]]
 
* [[Mathematics competition resources]]
 +
 +
 +
{{MAA Notice}}

Latest revision as of 14:23, 17 January 2023

1988 AJHSME (Answer Key)
Printable versions: Wiki • AoPS Resources • PDF

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 ? points for each correct answer, ? points for each problem left unanswered, and ? points for each incorrect answer.
  3. No aids are permitted other than scratch paper, graph paper, ruler, compass, protractor and erasers.
  4. Figures are not necessarily drawn to scale.
  5. You will have ? 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

The diagram shows part of a scale of a measuring device. The arrow indicates an approximate reading of

[asy] draw((-3,0)..(0,3)..(3,0)); draw((-3.5,0)--(-2.5,0)); draw((0,2.5)--(0,3.5)); draw((2.5,0)--(3.5,0)); draw((1.8,1.8)--(2.5,2.5)); draw((-1.8,1.8)--(-2.5,2.5)); draw((0,0)--3*dir(120),EndArrow); label("$10$",(-2.6,0),E); label("$11$",(2.6,0),W); [/asy]

$\text{(A)}\ 10.05 \qquad \text{(B)}\ 10.15 \qquad \text{(C)}\ 10.25 \qquad \text{(D)}\ 10.3 \qquad \text{(E)}\ 10.6$

Solution

Problem 2

The product $8\times .25\times 2\times .125 =$

$\text{(A)}\ \frac18 \qquad \text{(B)}\ \frac14 \qquad \text{(C)}\ \frac12 \qquad \text{(D)}\ 1 \qquad \text{(E)}\ 2$

Solution

Problem 3

$\frac{1}{10}+\frac{2}{20}+\frac{3}{30} =$

$\text{(A)}\ .1 \qquad \text{(B)}\ .123 \qquad \text{(C)}\ .2 \qquad \text{(D)}\ .3 \qquad \text{(E)}\ .6$

Solution

Problem 4

The figure consists of alternating light and dark squares. The number of dark squares exceeds the number of light squares by

$\text{(A)}\ 7 \qquad \text{(B)}\ 8 \qquad \text{(C)}\ 9 \qquad \text{(D)}\ 10 \qquad \text{(E)}\ 11$

[asy] unitsize(12); //Force a white background in middle even when transparent fill((3,1)--(12,1)--(12,4)--(3,4)--cycle,white); //Black Squares, Gray Border (blends better than white) for(int a=0; a<7; ++a) { filldraw((2a,0)--(2a+1,0)--(2a+1,1)--(2a,1)--cycle,black,gray); } for(int b=7; b<15; ++b) { filldraw((b,14-b)--(b+1,14-b)--(b+1,15-b)--(b,15-b)--cycle,black,gray); } for(int c=1; c<7; ++c) { filldraw((c,c)--(c+1,c)--(c+1,c+1)--(c,c+1)--cycle,black,gray); } filldraw((6,4)--(7,4)--(7,5)--(6,5)--cycle,black,gray); filldraw((7,5)--(8,5)--(8,6)--(7,6)--cycle,black,gray); filldraw((8,4)--(9,4)--(9,5)--(8,5)--cycle,black,gray); //White Squares, Black Border filldraw((7,4)--(8,4)--(8,5)--(7,5)--cycle,white,black); for(int a=0; a<7; ++a) { filldraw((2a+1,0)--(2a+2,0)--(2a+2,1)--(2a+1,1)--cycle,white,black); } for(int b=9; b<15; ++b) { filldraw((b-1,14-b)--(b,14-b)--(b,15-b)--(b-1,15-b)--cycle,white,black); } for(int c=1; c<7; ++c) { filldraw((c+1,c)--(c+2,c)--(c+2,c+1)--(c+1,c+1)--cycle,white,black); } label("same",(6.3,2.45),N); label("pattern here",(7.5,1.4),N); [/asy]

Solution

Problem 5

If $\angle \text{CBD}$ is a right angle, then this protractor indicates that the measure of $\angle \text{ABC}$ is approximately

[asy] unitsize(36); pair A,B,C,D; A=3*dir(160); B=origin; C=3*dir(110); D=3*dir(20); draw((1.5,0)..(0,1.5)..(-1.5,0)); draw((2.5,0)..(0,2.5)..(-2.5,0)--cycle); draw(A--B); draw(C--B); draw(D--B); label("O",(-2.5,0),W); label("A",A,W); label("B",B,S); label("C",C,W); label("D",D,E); label("0",(-1.8,0),W); label("20",(-1.7,.5),NW); label("160",(1.6,.5),NE); label("180",(1.7,0),E); [/asy]

$\text{(A)}\ 20^\circ \qquad \text{(B)}\ 40^\circ \qquad \text{(C)}\ 50^\circ \qquad \text{(D)}\ 70^\circ \qquad \text{(E)}\ 120^\circ$

Solution

Problem 6

$\frac{(.2)^3}{(.02)^2} =$

$\text{(A)}\ .2 \qquad \text{(B)}\ 2 \qquad \text{(C)}\ 10 \qquad \text{(D)}\ 15 \qquad \text{(E)}\ 20$

Solution

Problem 7

$2.46\times 8.163\times (5.17+4.829)$ is closest to

$\text{(A)}\ 100 \qquad \text{(B)}\ 200 \qquad \text{(C)}\ 300 \qquad \text{(D)}\ 400 \qquad \text{(E)}\ 500$

Solution

Problem 8

Betty used a calculator to find the product $0.075 \times 2.56$. She forgot to enter the decimal points. The calculator showed $19200$. If Betty had entered the decimal points correctly, the answer would have been

$\text{(A)}\ .0192 \qquad \text{(B)}\ .192 \qquad \text{(C)}\ 1.92 \qquad \text{(D)}\ 19.2 \qquad \text{(E)}\ 192$

Solution

Problem 9

An isosceles triangle is a triangle with two sides of equal length. How many of the five triangles on the square grid below are isosceles?

[asy] for(int a=0; a<12; ++a) { draw((a,0)--(a,6)); } for(int b=0; b<7; ++b) { draw((0,b)--(11,b)); } draw((0,6)--(2,6)--(1,4)--cycle,linewidth(1)); draw((3,4)--(3,6)--(5,4)--cycle,linewidth(1)); draw((0,1)--(3,2)--(6,1)--cycle,linewidth(1)); draw((7,4)--(6,6)--(9,4)--cycle,linewidth(1)); draw((8,1)--(9,3)--(10,0)--cycle,linewidth(1)); [/asy]

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

Solution

Problem 10

Chris's birthday is on a Thursday this year. What day of the week will it be $60$ days after her birthday?

$\text{(A)}\ \text{Monday} \qquad \text{(B)}\ \text{Wednesday} \qquad \text{(C)}\ \text{Thursday} \qquad \text{(D)}\ \text{Friday} \qquad \text{(E)}\ \text{Saturday}$

Solution

Problem 11

$\sqrt{164}$ is

$\text{(A)}\ 42 \qquad \text{(B)}\ \text{less than }10 \qquad \text{(C)}\ \text{between }10\text{ and }11 \qquad \text{(D)}\ \text{between }11\text{ and }12 \qquad \text{(E)}\ \text{between }12\text{ and }13$

Solution

Problem 12

Suppose the estimated $20$ billion dollar cost to send a person to the planet Mars is shared equally by the $250$ million people in the U.S. Then each person's share is

$\text{(A)}\ 20\text{ dollars} \qquad \text{(B)}\ 50\text{ dollars} \qquad \text{(C)}\ 80\text{ dollars} \qquad \text{(D)}\ 100\text{ dollars} \qquad \text{(E)}\ 125\text{ dollars}$

Solution

Problem 13

If rose bushes are spaced about $1$ foot apart, approximately how many bushes are needed to surround a circular patio whose radius is $12$ feet?

$\text{(A)}\ 12 \qquad \text{(B)}\ 38 \qquad \text{(C)}\ 48 \qquad \text{(D)}\ 75 \qquad \text{(E)}\ 450$

Solution

Problem 14

$\diamondsuit$ and $\Delta$ are whole numbers and $\diamondsuit \times \Delta =36$. The largest possible value of $\diamondsuit + \Delta$ is

$\text{(A)}\ 12 \qquad \text{(B)}\ 13 \qquad \text{(C)}\ 15 \qquad \text{(D)}\ 20\ \qquad \text{(E)}\ 37$

Solution

Problem 15

The reciprocal of $\left( \frac{1}{2}+\frac{1}{3}\right)$ is

$\text{(A)}\ \frac{1}{6} \qquad \text{(B)}\ \frac{2}{5} \qquad \text{(C)}\ \frac{6}{5} \qquad \text{(D)}\ \frac{5}{2} \qquad \text{(E)}\ 5$

Solution

Problem 16

Placing no more than one $\text{X}$ in each small square, what is the greatest number of $\text{X}$'s that can be put on the grid shown without getting three $\text{X}$'s in a row vertically, horizontally, or diagonally?

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

[asy] for(int a=0; a<4; ++a) { draw((a,0)--(a,3)); } for(int b=0; b<4; ++b) { draw((0,b)--(3,b)); } [/asy]

Solution

Problem 17

The shaded region formed by the two intersecting perpendicular rectangles, in square units, is

[asy] fill((0,0)--(6,0)--(6,-3.5)--(9,-3.5)--(9,0)--(10,0)--(10,2)--(9,2)--(9,4.5)--(6,4.5)--(6,2)--(0,2)--cycle,black); label("2",(0,.9),W); label("3",(7.3,4.5),N); draw((0,-3.3)--(0,-5.3),linewidth(1)); draw((0,-4.3)--(3.7,-4.3),linewidth(1)); label("10",(4.7,-3.7),S); draw((5.7,-4.3)--(10,-4.3),linewidth(1)); draw((10,-3.3)--(10,-5.3),linewidth(1)); draw((11,4.5)--(13,4.5),linewidth(1)); draw((12,4.5)--(12,2),linewidth(1)); label("8",(11.3,1),E); draw((12,0)--(12,-3.5),linewidth(1)); draw((11,-3.5)--(13,-3.5),linewidth(1)); [/asy]

$\text{(A)}\ 23 \qquad \text{(B)}\ 38 \qquad \text{(C)}\ 44 \qquad \text{(D)}\ 46 \qquad \text{(E)}\ \text{unable to be determined from the information given}$

Solution

Problem 18

The average weight of $6$ boys is $150$ pounds and the average weight of $4$ girls is $120$ pounds. The average weight of the $10$ children is

$\text{(A)}\ 135\text{ pounds} \qquad \text{(B)}\ 137\text{ pounds} \qquad \text{(C)}\ 138\text{ pounds} \qquad \text{(D)}\ 140\text{ pounds} \qquad \text{(E)}\ 141\text{ pounds}$

Solution

Problem 19

What is the $100\text{th}$ number in the arithmetic sequence: $1,5,9,13,17,21,25,...$?

$\text{(A)}\ 397 \qquad \text{(B)}\ 399 \qquad \text{(C)}\ 401 \qquad \text{(D)}\ 403 \qquad \text{(E)}\ 405$

Solution

Problem 20

The glass gauge on a cylindrical coffee maker shows that there are $45$ cups left when the coffee maker is $36\%$ full. How many cups of coffee does it hold when it is full?

$\text{(A)}\ 80 \qquad \text{(B)}\ 100 \qquad \text{(C)}\ 125 \qquad \text{(D)}\ 130 \qquad \text{(E)}\ 262$

[asy] draw((5,0)..(0,-1.3)..(-5,0)); draw((5,0)--(5,10)); draw((-5,0)--(-5,10)); draw(ellipse((0,10),5,1.3)); draw(circle((.3,1.3),.4)); draw((-.1,1.7)--(-.1,7.9)--(.7,7.9)--(.7,1.7)--cycle); fill((-.1,1.7)--(-.1,4)--(.7,4)--(.7,1.7)--cycle,black); draw((-2,11.3)--(2,11.3)..(2.6,11.9)..(2,12.2)--(-2,12.2)..(-2.6,11.9)..cycle); [/asy]

Solution

Problem 21

A fifth number, $n$, is added to the set $\{ 3,6,9,10 \}$ to make the mean of the set of five numbers equal to its median. The number of possible values of $n$ is

$\text{(A)}\ 1 \qquad \text{(B)}\ 2 \qquad \text{(C)}\ 3 \qquad \text{(D)}\ 4 \qquad \text{(E)}\ \text{more than }4$

Solution

Problem 22

Tom's Hat Shoppe increased all original prices by $25\%$. Now the shoppe is having a sale where all prices are $20\%$ off these increased prices. Which statement best describes the sale price of an item?

$\text{(A)}\ \text{The sale price is }5\% \text{ higher than the original price.}$

$\text{(B)}\ \text{The sale price is higher than the original price, but by less than }5\% .$

$\text{(C)}\ \text{The sale price is higher than the original price, but by more than }5\% .$

$\text{(D)}\ \text{The sale price is lower than the original price.}$

$\text{(E)}\ \text{The sale price is the same as the original price.}$

Solution

Problem 23

Maria buys computer disks at a price of $4$ for $<dollar>5$ and sells them at a price of $3$ for $<dollar>$$5$. How many computer disks must she sell in order to make a profit of $<dollar>100$?

$\text{(A)}\ 100 \qquad \text{(B)}\ 120 \qquad \text{(C)}\ 200 \qquad \text{(D)}\ 240 \qquad \text{(E)}\ 1200$

Solution

Problem 24

[asy] unitsize(15); for (int a=0; a<6; ++a) { draw(2*dir(60a)--2*dir(60a+60),linewidth(1)); } draw((1,1.7320508075688772935274463415059)--(1,3.7320508075688772935274463415059)--(-1,3.7320508075688772935274463415059)--(-1,1.7320508075688772935274463415059)--cycle,linewidth(1)); fill((.4,1.7320508075688772935274463415059)--(0,3.35)--(-.4,1.7320508075688772935274463415059)--cycle,black); label("1.",(0,-2),S); draw(arc((1,1.7320508075688772935274463415059),1,90,300,CW)); draw((1.5,0.86602540378443864676372317075294)--(1.75,1.7)); draw((1.5,0.86602540378443864676372317075294)--(2.2,1)); draw((7,0)--(6,1.7320508075688772935274463415059)--(4,1.7320508075688772935274463415059)--(3,0)--(4,-1.7320508075688772935274463415059)--(6,-1.7320508075688772935274463415059)--cycle,linewidth(1)); draw((7,0)--(6,1.7320508075688772935274463415059)--(7.7320508075688772935274463415059,2.7320508075688772935274463415059)--(8.7320508075688772935274463415059,1)--cycle,linewidth(1)); label("2.",(5,-2),S); draw(arc((7,0),1,30,240,CW)); draw((6.5,-0.86602540378443864676372317075294)--(7.1,-.7)); draw((6.5,-0.86602540378443864676372317075294)--(6.8,-1.5)); draw((14,0)--(13,1.7320508075688772935274463415059)--(11,1.7320508075688772935274463415059)--(10,0)--(11,-1.7320508075688772935274463415059)--(13,-1.7320508075688772935274463415059)--cycle,linewidth(1)); draw((14,0)--(13,-1.7320508075688772935274463415059)--(14.7320508075688772935274463415059,-2.7320508075688772935274463415059)--(15.7320508075688772935274463415059,-1)--cycle,linewidth(1)); label("3.",(12,-2.5),S); draw((21,0)--(20,1.7320508075688772935274463415059)--(18,1.7320508075688772935274463415059)--(17,0)--(18,-1.7320508075688772935274463415059)--(20,-1.7320508075688772935274463415059)--cycle,linewidth(1)); draw((18,-1.7320508075688772935274463415059)--(20,-1.7320508075688772935274463415059)--(20,-3.7320508075688772935274463415059)--(18,-3.7320508075688772935274463415059)--cycle,linewidth(1)); label("4.",(19,-4),S); [/asy]

The square in the first diagram "rolls" clockwise around the fixed regular hexagon until it reaches the bottom. In which position will the solid triangle be in diagram $4$?

[asy] unitsize(12); label("(A)",(0,0),W); fill((1,-1)--(1,1)--(5,0)--cycle,black); label("(B)",(6,0),E); fill((9,-2)--(11,-2)--(10,1)--cycle,black); label("(C)",(14,0),E); fill((17,1)--(19,1)--(18,-1.8)--cycle,black); label("(D)",(22,0),E); fill((25,-1)--(27,-2)--(28,1)--cycle,black); label("(E)",(31,0),E); fill((33,0)--(37,1)--(37,-1)--cycle,black); [/asy]

Solution

Problem 25

A palindrome is a whole number that reads the same forwards and backwards. If one neglects the colon, certain times displayed on a digital watch are palindromes. Three examples are: $\boxed{1:01}$, $\boxed{4:44}$, and $\boxed{12:21}$. How many times during a $12$-hour period will be palindromes?

$\text{(A)}\ 57 \qquad \text{(B)}\ 60 \qquad \text{(C)}\ 63 \qquad \text{(D)}\ 90 \qquad \text{(E)}\ 93$

Solution

See also

1988 AJHSME (Problems • Answer Key • Resources)
Preceded by
1987 AJHSME 		Followed by
1989 AJHSME
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 AJHSME/AMC 8 Problems and Solutions


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