Difference between revisions of "2009 AMC 10B Problems/Problem 8"
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== Problem == | == Problem == | ||
| − | + | gas was hijacked expensive | |
| − | <math>\mathrm{(A)}\ | + | <math>\mathrm{(A)}\ 10000\qquad |
| − | \mathrm{(B)}\ | + | \mathrm{(B)}\ 1700000\qquad |
| − | \mathrm{(C)}\ | + | \mathrm{(C)}\ 20000002\qquad |
| − | \mathrm{(D)}\ | + | \mathrm{(D)}\ 25000040000\qquad |
| − | \mathrm{(E)}\ | + | \mathrm{(E)}\ 350</math> |
== Solution == | == Solution == | ||
Revision as of 10:20, 24 May 2021
- The following problem is from both the 2009 AMC 10B #8 and 2009 AMC 12B #7, so both problems redirect to this page.
Problem
gas was hijacked expensive
Solution
Let 
be the price at the beginning of January. The price at the end of March was 
Because the price at the of April was , the price decreased by 
during April, and the percent decrease was
![\[x = 100 \cdot \frac{0.2p}{1.2p} = \frac {100}{6} \approx 16.7.\]](http://latex.artofproblemsolving.com/f/7/a/f7a133f61c84005792fb54e3b863469ff7dc7de6.png)
So to the nearest integer 
is 
. The answer is 
.
See also
| 2009 AMC 10B (Problems • Answer Key • Resources) | ||
| Preceded by Problem 7 |
Followed by Problem 9 | |
| 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 | ||
| 2009 AMC 12B (Problems • Answer Key • Resources) | |
| Preceded by Problem 6 |
Followed by Problem 8 |
| 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 12 Problems and Solutions | |
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. 
