Difference between revisions of "2008 AMC 12A Problems/Problem 1"

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==Problem ==
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A bakery owner turns on his doughnut machine at 8:30 AM. At 11:10 AM the machine has completed one third of the day's job. At what time will the doughnut machine complete the job?
  
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<math>\textbf{(A)} \text{ 1:50 PM } \qquad \textbf{(B)} \text{ 3:00 PM } \qquad \textbf{(C)} \text{ 3:30 PM } \qquad \textbf{(D)} \text{ 4:30 PM } \qquad \textbf{(E)} \text{ 5:50 PM }</math>
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==Solution==
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The machine completes one third of the job in <math>\text{11:10}-\text{8:30}=\text{2:40}</math>. Thus the entire job is completed in <math>3 \cdot (\text{2:40}) = \text{8:00}</math>. Since the machine is started at <math>\text{8:30 AM}</math>, the job is finished <math>8</math> hours later at <math>\text{4:30 PM}\Rightarrow D</math>
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==See Also==
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{{AMC12 box|year=2008|ab=A|before=First question|num-a=2}}

Revision as of 14:41, 17 February 2008

Problem

A bakery owner turns on his doughnut machine at 8:30 AM. At 11:10 AM the machine has completed one third of the day's job. At what time will the doughnut machine complete the job?

$\textbf{(A)} \text{ 1:50 PM } \qquad \textbf{(B)} \text{ 3:00 PM } \qquad \textbf{(C)} \text{ 3:30 PM } \qquad \textbf{(D)} \text{ 4:30 PM } \qquad \textbf{(E)} \text{ 5:50 PM }$

Solution

The machine completes one third of the job in $\text{11:10}-\text{8:30}=\text{2:40}$. Thus the entire job is completed in $3 \cdot (\text{2:40}) = \text{8:00}$. Since the machine is started at $\text{8:30 AM}$, the job is finished $8$ hours later at $\text{4:30 PM}\Rightarrow D$

See Also

2008 AMC 12A (ProblemsAnswer KeyResources)
Preceded by
First question
Followed by
Problem 2
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All AMC 12 Problems and Solutions
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