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Difference between revisions of "2005 AMC 12B Problems"

(Problem 2)
(Problem 3)
Line 26: Line 26:
  
 
== Problem 3 ==
 
== Problem 3 ==
A rectangle with a diagonal of length <math>x</math> is twice as long as it is wide. What is the area of the rectangle?
+
Brianna is using part of the money she earned on her weekend job to buy several equally-priced CDs. She used one fifth of her money to buy one third of the CDs. What fraction of her money will she have left after she buys all the CDs?  
  
 
<math>
 
<math>
\mathrm{(A)}\ \frac14x^2     \qquad
+
\mathrm{(A)}\ \frac15     \qquad
\mathrm{(B)}\ \frac25x^2     \qquad
+
\mathrm{(B)}\ \frac13     \qquad
\mathrm{(C)}\ \frac12x^2     \qquad
+
\mathrm{(C)}\ \frac25     \qquad
\mathrm{(D)}\ x^2     \qquad
+
\mathrm{(D)}\ \frac23     \qquad
\mathrm{(E)}\ \frac32x^2
+
\mathrm{(E)}\ \frac45
 
</math>
 
</math>
  

Revision as of 21:10, 17 April 2009

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Problem 1

A scout troop buys $1000$ candy bars at a price of five for $2$ dollars. They sell all the candy bars at the price of two for $1$ dollar. What was their profit, in dollars?

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

Solution

Problem 2

A positive number $x$ has the property that $x\%$ of $x$ is $4$. What is $x$? $\mathrm{(A)}\ 2      \qquad \mathrm{(B)}\ 4      \qquad \mathrm{(C)}\ 10      \qquad \mathrm{(D)}\ 20      \qquad \mathrm{(E)}\ 40$

Solution

Problem 3

Brianna is using part of the money she earned on her weekend job to buy several equally-priced CDs. She used one fifth of her money to buy one third of the CDs. What fraction of her money will she have left after she buys all the CDs?

$\mathrm{(A)}\ \frac15      \qquad \mathrm{(B)}\ \frac13      \qquad \mathrm{(C)}\ \frac25      \qquad \mathrm{(D)}\ \frac23      \qquad \mathrm{(E)}\ \frac45$

Solution

Problem 4

The average (mean) of $20$ numbers is $30, and the average of$30$other numbers is$20$.  What is the average of$ \mathrm{(A)}\ \frac14x^2 \qquad \mathrm{(B)}\ \frac25x^2 \qquad \mathrm{(C)}\ \frac12x^2 \qquad \mathrm{(D)}\ x^2 \qquad \mathrm{(E)}\ \frac32x^2 $

Solution

Problem 5

Solution

Problem 6

Solution

Problem 7

Solution

Problem 8

Solution

Problem 9

Solution

Problem 10

Solution

Problem 11

Solution

Problem 12

Solution

Problem 13

Solution

Problem 14

Solution

Problem 15

Solution

Problem 16

Solution

Problem 17

Solution

Problem 18

Solution

Problem 19

Solution

Problem 20

Solution

Problem 21

Solution

Problem 22

Solution

Problem 23

Solution

Problem 24

Solution

Problem 25

Solution

See also