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Difference between revisions of "2005 AMC 12B Problems"
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== Problem 4 == | == Problem 4 == | ||
| + | The average (mean) of <math>20</math> numbers is <math>30, and the average of </math>30<math> other numbers is </math>20<math>. What is the average of | ||
| + | |||
| + | </math> | ||
| + | \mathrm{(A)}\ \frac14x^2 \qquad | ||
| + | \mathrm{(B)}\ \frac25x^2 \qquad | ||
| + | \mathrm{(C)}\ \frac12x^2 \qquad | ||
| + | \mathrm{(D)}\ x^2 \qquad | ||
| + | \mathrm{(E)}\ \frac32x^2 | ||
| + | $ | ||
[[2005 AMC 12B Problems/Problem 4|Solution]] | [[2005 AMC 12B Problems/Problem 4|Solution]] | ||
Revision as of 20:49, 17 April 2009
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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
Two is 
of 
and 
of 
. What is 
?
Problem 2
The equations 
and 
have the same solution for . What is the value of 
?
Problem 3
A rectangle with a diagonal of length is twice as long as it is wide. What is the area of the rectangle?
Problem 4
The average (mean) of 
numbers is 
30
20
\mathrm{(A)}\ \frac14x^2 \qquad
\mathrm{(B)}\ \frac25x^2 \qquad
\mathrm{(C)}\ \frac12x^2 \qquad
\mathrm{(D)}\ x^2 \qquad
\mathrm{(E)}\ \frac32x^2
$
