<PRE><B>Question 1056619</B>
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/(2s)}}} + {{{10/s}}} = 2.5
Cancel the 2 in the first fraction
{{{10/s}}} + {{{10/s}}} = 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</PRE>