Difference between revisions of "2015 AMC 8 Problems/Problem 3"

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==Problem==
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Jack and Jill are going swimming at a pool that is one mile from their house. They leave home simultaneously. Jill rides her bicycle to the pool at a constant speed of <math>10</math> miles per hour. Jack walks to the pool at a constant speed of <math>4</math> miles per hour. How many minutes before Jack does Jill arrive?
 
Jack and Jill are going swimming at a pool that is one mile from their house. They leave home simultaneously. Jill rides her bicycle to the pool at a constant speed of <math>10</math> miles per hour. Jack walks to the pool at a constant speed of <math>4</math> miles per hour. How many minutes before Jack does Jill arrive?
  
 
<math>\textbf{(A) }5\qquad\textbf{(B) }6\qquad\textbf{(C) }8\qquad\textbf{(D) }9\qquad \textbf{(E) }10</math>
 
<math>\textbf{(A) }5\qquad\textbf{(B) }6\qquad\textbf{(C) }8\qquad\textbf{(D) }9\qquad \textbf{(E) }10</math>
  
===Solution===
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==Solution==
Jill arrives in <math>\dfrac{1}{10}</math> of an hour, which is <math>6</math> minutes. Jack arrives in <math>\dfrac{1}{4}</math> of an hour which is <math>15</math> minutes. Thus, the time difference is <math>\boxed{\textbf{(D)}~9}</math> minutes.
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Using <math>d=rt</math>, we can set up an equation for when Jill arrives at the swimming pool:
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<math>1=10t</math>
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Solving for <math>t</math>, we get that Jill gets to the pool in <math>\frac{1}{10}</math> of an hour, which is <math>6</math> minutes. Doing the same for Jack, we get that
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Jack arrives at the pool in <math>\frac{1}{4}</math> of an hour, which in turn is <math>15</math> minutes. Thus, Jill has to wait <math>15-6=\boxed{\textbf{(D)}~9}</math>  
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minutes for Jack to arrive at the pool.
  
 
==Solution 2==
 
==Solution 2==
Using <math>d=rt</math>, we can set up an equation for when Jill arrives at swimming:
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T=D/s
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Jill: (1/10)x60 because in minutes, is equal to 6 min
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Jack:(1/4)x60 is 15 minutes.
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15-6 is 9, so our answer is <math>15-6=\boxed{\textbf{(D)}~9}</math> - TheNerdWhoIsNerdy.
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==Video Solution (HOW TO THINK CRITICALLY!!!)==
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https://youtu.be/srGyMofBMsE
  
<math>1=10t</math>
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~Education, the Study of Everything
  
Solving for <math>t</math>, we get that Jill gets to the pool in <math>\frac{1}{10}</math> of on hour, which translates to <math>6</math> minutes.  Doing the same for Jack, we get that
 
  
Jack arrives at the pool in <math>\frac{1}{4}</math> of an hour, which in turn translates to <math>15</math> minutes. Thus, Jill has to wait <math>15-6=\boxed{\textbf{9}}</math>
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==Video Solution==
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https://youtu.be/YvYq3iM4jP8
  
minutes for Jack to arrive at the pool: Therefore, the answer is <math>\boxed{{\textbf{(D) 9} }}</math>.
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~savannahsolver
  
 
==See Also==
 
==See Also==

Latest revision as of 19:24, 15 September 2024

Problem

Jack and Jill are going swimming at a pool that is one mile from their house. They leave home simultaneously. Jill rides her bicycle to the pool at a constant speed of $10$ miles per hour. Jack walks to the pool at a constant speed of $4$ miles per hour. How many minutes before Jack does Jill arrive?

$\textbf{(A) }5\qquad\textbf{(B) }6\qquad\textbf{(C) }8\qquad\textbf{(D) }9\qquad \textbf{(E) }10$

Solution

Using $d=rt$, we can set up an equation for when Jill arrives at the swimming pool:

$1=10t$

Solving for $t$, we get that Jill gets to the pool in $\frac{1}{10}$ of an hour, which is $6$ minutes. Doing the same for Jack, we get that

Jack arrives at the pool in $\frac{1}{4}$ of an hour, which in turn is $15$ minutes. Thus, Jill has to wait $15-6=\boxed{\textbf{(D)}~9}$

minutes for Jack to arrive at the pool.

Solution 2

T=D/s Jill: (1/10)x60 because in minutes, is equal to 6 min Jack:(1/4)x60 is 15 minutes. 15-6 is 9, so our answer is $15-6=\boxed{\textbf{(D)}~9}$ - TheNerdWhoIsNerdy.

Video Solution (HOW TO THINK CRITICALLY!!!)

https://youtu.be/srGyMofBMsE

~Education, the Study of Everything


Video Solution

https://youtu.be/YvYq3iM4jP8

~savannahsolver

See Also

2015 AMC 8 (ProblemsAnswer KeyResources)
Preceded by
Problem 2
Followed by
Problem 4
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All AJHSME/AMC 8 Problems and Solutions

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