Question 107632
Tina can run 12 mi in the same time it takes her to bicycle
72 mi. If her bicycling rate is 20 mi/h faster than her running rate, find each
:
Let s = T's running speed
then
(s+20) = T's cycling speed
:
Run time = cycling time
:
Time = Dist/speed
:
{{{12/s}}} = {{{72/((s+20))}}}
:
Cross multiply:
72s = 12(s+20)
:
72s = 12s + 240
:
72s - 12s = 240
:
60s = 240
:
s = 240/60
:
s = 4 mph is T's running speed
Then
24 mph is T's cycling speed
:
:
Check solution by find the times:
12/4 = 3 hrs
72/24 = 3 hrs, confirms our solutions