very very very urgent...

Asked by anju.b.thomas | 22nd Dec, 2009, 08:05: AM

Expert Answer:

Let the distance from his place to school be x m.

Time required to reach school = x/20

Time required for return trip = x/30

Average speed = total distance/total time.

= 2x/(x/20 + x/30)

= 2/(1/20 + 1/30) = 24 km/hr.

Regards,

Team,

TopperLearning.

Answered by  | 22nd Dec, 2009, 11:26: AM

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