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Difference between revisions of "2004 AMC 8 Problems"

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(→‎Problem 12)
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==Problem 12==
 
==Problem 12==
 +
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Niki usually leaves her cell phone on. If her cell phone is on but
 +
she is not actually using it, the battery will last for <math>24</math> hours. If
 +
she is using it constantly, the battery will last for only <math>3</math> hours.
 +
Since the last recharge, her phone has been on <math>9</math> hours, and during
 +
that time she has used it for <math>60</math> minutes. If she doesn’t talk any
 +
more but leaves the phone on, how many more hours will the battery last?
 +
 +
<math> \mathrm{(A)\ 7 }\qquad\mathrm{(B)\ 8 }\qquad\mathrm{(C)\ 11 }\qquad\mathrm{(D)\ 14 }\qquad\mathrm{(E)\ 15 } </math>
  
 
==Problem 13==
 
==Problem 13==

Revision as of 22:39, 21 October 2011

Problem 1

Ona map, a $12$-centimeter length represents $72$ kilometers. How many kilometers does a $17$-centimeter length represent?

$\textbf{(A)}\ 6\qquad\textbf{(B)}\ 102\qquad\textbf{(C)}\ 204\qquad\textbf{(D)}\ 864\qquad\textbf{(E)}\ 1224$

Problem 2

How many different four-digit numbers can be formed be rearranging the four digits in $2004$?

$\textbf{(A)}\ 4\qquad\textbf{(B)}\ 6\qquad\textbf{(C)}\ 16\qquad\textbf{(D)}\ 24\qquad\textbf{(E)}\ 81$

Problem 3

Twelve friends met for dinner at Oscar's Overstuffed Oyster House, and each ordered one meal. The portions were so large, there was enough food for $18$ people. If they shared, how many meals should they have ordered to have just enough food for the $12$ of them?

$\textbf{(A)}\ 8\qquad\textbf{(B)}\ 9\qquad\textbf{(C)}\ 10\qquad\textbf{(D)}\ 15\qquad\textbf{(E)}\ 18$

Problem 4

The following information is needed to solve problems 4, 5 and 6.

Ms. Hamilton’s eighth-grade class wants to participate in the annual three-person-team basketball tournament.

Lance, Sally, Joy, and Fred are chosen for the team. In how many ways can the three starters be chosen?

$\textbf{(A)}2\qquad\textbf{(B)}4\qquad\textbf{(C)}6\qquad\textbf{(D)}8\qquad\textbf{(E)}10$

Problem 5

The losing team of each game is eliminated from the tournament. If sixteen teams compete, how many games will be played to determine the winner?

$\textbf{(A)}4\qquad\textbf{(B)}7\qquad\textbf{(C)}8\qquad\textbf{(D)}15\qquad\textbf{(E)}16$

Problem 6

After Sally takes $20$ shots, she has made $55\%$ of her shots. After she takes $5$ more shots, she raises her percentage to $56\%$. How many of the last $5$ shots did she make?

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

Problem 7

An athlete's target heart rate, in beats per minute, is $80\%$ of the theoretical maximum heart rate. The maximum heart rate is found by subtracting the athlete's age, in years, from $220$. To the nearest whole number, what is the target heart rate of an athlete who is $26$ years old?

$\textbf{(A)}\ 134\qquad\textbf{(B)}\ 155\qquad\textbf{(C)}\ 176\qquad\textbf{(D)}\ 194\qquad\textbf{(E)}\ 243$

Problem 8

Find the number of two-digit positive integers whose digits total $7$.

$\mathrm{(A)\ 6 }\qquad\mathrm{(B)\ 7 }\qquad\mathrm{(C)\ 8 }\qquad\mathrm{(D)\ 9 }\qquad\mathrm{(E)\ 10 }$

Problem 9

The average of the five numbers in a list is $54$. The average of the first two numbers is $48$. What is the average of the last three numbers?

$\mathrm{(A)\ 55 }\qquad\mathrm{(B)\ 56 }\qquad\mathrm{(C)\ 57 }\qquad\mathrm{(D)\ 58 }\qquad\mathrm{(E)\ 59 }$

Problem 10

Problem 11

The numbers $-2$, $4$, $6$, $9$ and $12$ are rearranged according to these rules: 

        1. The largest isn’t first, but it is in one of the first three places. 
        2. The smallest isn’t last, but it is in one of the last three places. 
        3. The median isn’t first or last.

What is the average of the first and last numbers?

$\mathrm{(A)\ 3.5 }\qquad\mathrm{(B)\ 5 }\qquad\mathrm{(C)\ 6.5 }\qquad\mathrm{(D)\ 7.5 }\qquad\mathrm{(E)\ 8 }$

Problem 12

Niki usually leaves her cell phone on. If her cell phone is on but she is not actually using it, the battery will last for $24$ hours. If she is using it constantly, the battery will last for only $3$ hours. Since the last recharge, her phone has been on $9$ hours, and during that time she has used it for $60$ minutes. If she doesn’t talk any more but leaves the phone on, how many more hours will the battery last?

$\mathrm{(A)\ 7 }\qquad\mathrm{(B)\ 8 }\qquad\mathrm{(C)\ 11 }\qquad\mathrm{(D)\ 14 }\qquad\mathrm{(E)\ 15 }$

Problem 13

Problem 14

Problem 15

Problem 16

Problem 17

Problem 18

Problem 19

Problem 20

Problem 21

Problem 22

Problem 23

Problem 24

Problem 25

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