Question 903489
Running at an average rate of 5 meters per second, a sprinter ran to the end of a track.
 The sprinter then jogged back to the starting point at an average rate of 2 meters per second.
 The total time for the sprint and the jog back was 2 minutes 27 seconds.
 Find the length of the track.
:
let d = the length of the track
:
Change 2 min 27 sec to 147 sec
:
Write a time equation; time = dist/speed
run time + jog time = 147 sec
{{{d/5}}} + {{{d/2}}} = 147
multiply by 10 to get rid of the deliminators
2d + 5d = 10(147)
7d = 1470
d = 1470/7
d = 210 meters
:
:
Check it, find the actual time each way
210/5 = 42 sec
210/2 = 105 sec
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total: 147 sec