Difference between revisions of "2000 AMC 10 Problems/Problem 3"

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<math>x \cdot .8 \cdot .8=32</math>
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==Problem==
  
<math>x \cdot .64=32</math>
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Each day, Jenny ate <math>20\%</math> of the jellybeans that were in her jar at the beginning of that day. At the end of the second day, <math>32</math> remained. How many jellybeans were in the jar originally?
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<math>\mathrm{(A)}\ 40 \qquad\mathrm{(B)}\ 50 \qquad\mathrm{(C)}\ 55 \qquad\mathrm{(D)}\ 60 \qquad\mathrm{(E)}\ 75</math>
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==Solution==
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<math>x(.8)(.8)=32</math>
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<math>x(.64)=32</math>
  
 
<math>x \cdot \frac{32}{50}=32</math>
 
<math>x \cdot \frac{32}{50}=32</math>
  
<math>x=50</math>.
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<math>x=50</math>
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<math>\boxed{\text{B}}</math>
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==See Also==
  
B.
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{{AMC10 box|year=2000|num-b=2|num-a=4}}

Revision as of 17:58, 8 January 2009

Problem

Each day, Jenny ate $20\%$ of the jellybeans that were in her jar at the beginning of that day. At the end of the second day, $32$ remained. How many jellybeans were in the jar originally?

$\mathrm{(A)}\ 40 \qquad\mathrm{(B)}\ 50 \qquad\mathrm{(C)}\ 55 \qquad\mathrm{(D)}\ 60 \qquad\mathrm{(E)}\ 75$

Solution

$x(.8)(.8)=32$

$x(.64)=32$

$x \cdot \frac{32}{50}=32$

$x=50$

$\boxed{\text{B}}$

See Also

2000 AMC 10 (ProblemsAnswer KeyResources)
Preceded by
Problem 2
Followed by
Problem 4
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