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

m
(Categorized problem)
 
(24 intermediate revisions by 18 users not shown)
Line 1: Line 1:
4. When Cheenu was a boy he could run <math>15</math> miles in <math>3</math> hours and <math>30</math> minutes. As an old man he can now walk <math>10</math> miles in <math>4</math> hours. How many minutes longer does it take for him to walk a mile now compared to when he was a boy?
+
== Problem ==
 +
 
 +
When Cheenu was a boy, he could run <math>15</math> miles in <math>3</math> hours and <math>30</math> minutes. As an old man, he can now walk <math>10</math> miles in <math>4</math> hours. How many minutes longer does it take for him to walk a mile now compared to when he was a boy?
  
 
<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==
+
== Solution 1 ==
{{solution}}
+
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
 +
 
 +
== Solution 2 ==
 +
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>
 +
 
 +
== 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 ==
 +
{{AMC8 box|year=2016|num-b=3|num-a=5}}
 +
{{MAA Notice}}
 +
[[Category:Introductory Algebra Problems]]

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

These problems are copyrighted © by the Mathematical Association of America, as part of the American Mathematics Competitions. AMC logo.png