Question 917702: Two persons are to run a race, but one can run 12 meters per second, whereas the other can run 6 meters per second. If the slower runner has a 63-meter head start, how long will it be before the faster runner catches the slower runner, if they begin at the same time?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! Two persons are to run a race, but one can run 12 meters per second, whereas the other can run 6 meters per second.
If the slower runner has a 63-meter head start, how long will it be before the faster runner catches the slower runner, if they begin at the same time?
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Just thinking about it, if one is running twice as fast as the other, he would cover twice the distance, in the same time or 126 ft; 126/12 = 10.5 sec
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But here is a method, that will work for any pair of runner speeds.
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Let d = distance ran by the slower runner
then
(d+63) = distance ran by the faster runner
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Write a time equation time = dist/speed
 = 
cross multiply
12d = 6(d+63)
12d = 6d + 378
12d - 6d = 378
d = 378/6
d = 63 meters
find the time
63/6 = 10.5 sec
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