Difference between revisions of "2016 AMC 8 Problems/Problem 4"

(Video Solution (THINKING CREATIVELY!!!))
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<math>\textbf{(A) }6\qquad\textbf{(B) }10\qquad\textbf{(C) }15\qquad\textbf{(D) }18\qquad \textbf{(E) }30</math>
 
<math>\textbf{(A) }6\qquad\textbf{(B) }10\qquad\textbf{(C) }15\qquad\textbf{(D) }18\qquad \textbf{(E) }30</math>
  
==Solution==
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== Solution 1 ==
 
When Cheenu was a boy, he could run <math>15</math> miles in <math>3</math> hours and <math>30</math> minutes <math>= 3\times60 + 30</math> minutes <math>= 210</math> minutes, thus running <math>\frac{210}{15} = 14</math> minutes per mile. Now that he is an old man, he can walk <math>10</math> miles in <math>4</math> hours <math>= 4 \times 60</math> minutes <math>= 240</math> minutes, thus walking <math>\frac{240}{10} = 24</math> minutes per mile. Therefore, it takes him <math>\boxed{\textbf{(B)}\ 10}</math> minutes longer to walk a mile now compared to when he was a boy.
 
When Cheenu was a boy, he could run <math>15</math> miles in <math>3</math> hours and <math>30</math> minutes <math>= 3\times60 + 30</math> minutes <math>= 210</math> minutes, thus running <math>\frac{210}{15} = 14</math> minutes per mile. Now that he is an old man, he can walk <math>10</math> miles in <math>4</math> hours <math>= 4 \times 60</math> minutes <math>= 240</math> minutes, thus walking <math>\frac{240}{10} = 24</math> minutes per mile. Therefore, it takes him <math>\boxed{\textbf{(B)}\ 10}</math> minutes longer to walk a mile now compared to when he was a boy.
  
 
~CHECKMATE2021
 
~CHECKMATE2021
  
==Video Solution==
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== Solution 2 ==
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From the question, the old man can travel five miles in two hours, so we can set both speeds to <math>15</math> miles. We can see that Cheenu as an old man takes <math>2</math> hours and <math>30</math> minutes for him to travel <math>15</math> miles, which is also <math>150</math> minutes. We can then divide this by fifteen, which gives us <math>10</math>, thus the answer is <math>\boxed{\textbf{B) 10}}</math>
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== Video Solution ==
  
 
https://youtu.be/I9neY-xoG90?si=tDSd8my8W8Mb7Lqp
 
https://youtu.be/I9neY-xoG90?si=tDSd8my8W8Mb7Lqp
  
A solution so simple a 12-year-old made it!
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~Elijahman~
  
~Elijahman~
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== Video Solution (THINKING CREATIVELY!!!) ==
==Video Solution (THINKING CREATIVELY!!!)==
 
 
https://youtu.be/r92zdVMTamI
 
https://youtu.be/r92zdVMTamI
  
 
~Education, the Study of Everything
 
~Education, the Study of Everything
  
==Video Solution==
+
== Video Solution ==
  
 
https://youtu.be/gKjWxvyNSjk
 
https://youtu.be/gKjWxvyNSjk
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~savannahsolver
 
~savannahsolver
  
==See Also==
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== See Also ==
 
{{AMC8 box|year=2016|num-b=3|num-a=5}}
 
{{AMC8 box|year=2016|num-b=3|num-a=5}}
 
{{MAA Notice}}
 
{{MAA Notice}}
 
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[[Category:Introductory Algebra Problems]]
Another Solution
 
From the question, the old man can travel five miles in two hours, so we can set both speeds to 15 miles. We can see that Cheenu as an old man takes 2hrs 30mins for him to travel 15 miles, which is also 150 minutes. We can then divide this by fifteen, which gives us 10, so the answwer is B) 10
 

Latest revision as of 18:00, 25 June 2025

Problem

When Cheenu was a boy, he could run $15$ miles in $3$ hours and $30$ minutes. As an old man, he can now walk $10$ miles in $4$ hours. How many minutes longer does it take for him to walk a mile now compared to when he was a boy?

$\textbf{(A) }6\qquad\textbf{(B) }10\qquad\textbf{(C) }15\qquad\textbf{(D) }18\qquad \textbf{(E) }30$

Solution 1

When Cheenu was a boy, he could run $15$ miles in $3$ hours and $30$ minutes $= 3\times60 + 30$ minutes $= 210$ minutes, thus running $\frac{210}{15} = 14$ minutes per mile. Now that he is an old man, he can walk $10$ miles in $4$ hours $= 4 \times 60$ minutes $= 240$ minutes, thus walking $\frac{240}{10} = 24$ minutes per mile. Therefore, it takes him $\boxed{\textbf{(B)}\ 10}$ minutes longer to walk a mile now compared to when he was a boy.

~CHECKMATE2021

Solution 2

From the question, the old man can travel five miles in two hours, so we can set both speeds to $15$ miles. We can see that Cheenu as an old man takes $2$ hours and $30$ minutes for him to travel $15$ miles, which is also $150$ minutes. We can then divide this by fifteen, which gives us $10$, thus the answer is $\boxed{\textbf{B) 10}}$

Video Solution

https://youtu.be/I9neY-xoG90?si=tDSd8my8W8Mb7Lqp

~Elijahman~

Video Solution (THINKING CREATIVELY!!!)

https://youtu.be/r92zdVMTamI

~Education, the Study of Everything

Video Solution

https://youtu.be/gKjWxvyNSjk

~savannahsolver

See Also

2016 AMC 8 (ProblemsAnswer KeyResources)
Preceded by
Problem 3
Followed by
Problem 5
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 AJHSME/AMC 8 Problems and Solutions

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