Question

A train travels the first 15km at uniform speed of 30km/h next 10 km at uniform speed of 20 km/h and final 75 km at uniform speed of 50 km/h . the average speed for the entire journey of the train ?

Answer 1

t1=15/30=0.5h
t2=10/20=0.5h
t3=75/50=1.5h
avg speed=(15+10+75)/(0.5+0.5+1.5)
=100/2.5
=40km/hr