A train goes from Ballygunge to Sealdah at an average speed

A train goes from Ballygunge to Sealdah at an average speed of 20 km/hour and comes back at an average speed of 30 km/hour. The average speed of the train for the whole journey is

Required average speed =	2 × 30 × 20
	30 + 20

[∵ Distance covered is same]

=	2 × 30 × 20	= 24 kmph
	50