Question

A train travel with a speed of 60 km/hr to station a to b then come back with a speed 80 km/ hr from station b to a find the average speed

Answer 1

Here you go....

Average velocity will be zero(0) as the train returned back to station A so there is no displacement (since velocity=displacement/time). Average speed :- Let distance(dist) between A and B=x Case 1(A TO B) speed=60 kmph dist=x therefore, time=x/60 Case 1(B TO A) speed=80 kmph dist=x therefore, time= x/80 Since, average speed = total dist/total time Therefore, average speed= x+x ----------- x/60+x/80 = 2x ------------ 4x+3x/240 = 2x ------------ 7x/240 =2x*240/7x (x cancels with x) =480/7 =68.57 kmph(approx)

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