Question

A train travels some distance with a speed of 30 kilometre per hour and returns with a speed of 45 km per hour calculate the average speed of a train​

Answer 1

Answer:

v1=30km/h

v2=45km/h

average speed=(2v1.v2)/(v1+v2)

(2×30×45) /(30+45)

2700/75=36km/h

Answer 2

let the total path to be covered be s

then total distance covered by the train is 2s

time taken for first journey is s/30

time taken for second journey is s/45

average speed=total distance/total time taken

=s+s/(s/45+s/30)

=36 km/hr

Aliter:

just apply the formula

V avg=2*V1*V2/V1+V2

Hope this helps