Question

A train moves with a speed of 30 kmph for 12 minutes and for next 8 minutes at a speed of 45 kmph. Find the average speed of the train:

Answer 1

average distance=total distance /total time
distance1 = 13x12
=156
distance 2= 45x8
=360
now,
total distance=360+156
=516
total time = 12+8
=20
therefore,
average speed= 516/20
=25.8kmph^-1



hope it will help
be brainy Budd.....

Answer 2

Avg speed = total distance/Total time
so, Total Distance = 30*12/60 + 45*8/60
=12 Km
and Total time = 1/3 hr
so, Avg speed = 36Kmph