SOLUTION: An athlete in training rides his bike 20 mi and then immediately follows with a 10-mi run. The total workout takes him 2.5 hr. He also knows that he bikes about twice as fast as he

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Question 1056619: An athlete in training rides his bike 20 mi and then immediately follows with a 10-mi run. The total workout takes him 2.5 hr. He also knows that he bikes about twice as fast as he runs. Determine his biking speed and his running speed.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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An athlete in training rides his bike 20 mi and then immediately follows with a 10-mi run.
The total workout takes him 2.5 hr.
He also knows that he bikes about twice as fast as he runs.
Determine his biking speed and his running speed.
:
let s = the running speed
then
2s = his biking speed
;
Write a time equation; time = dist/speed
Bike time + Run time = 2.5 hrs
20%2F%282s%29 + 10%2Fs = 2.5
Cancel the 2 in the first fraction
10%2Fs + 10%2Fs = 2.5
multiply by s
10 + 10 = 2.5s
20 = 2.5s
s = 20/2.5
s = 8 mph is his running speed (His biking speed is too obvious)
:
Check by finding the time of each total