A man covers the journey from a station A to station B at

A man covers the journey from a station A to station B at a uniform speed of 36 km/hr and
returns to A with a uniform speed of 45 km/hr. His average speed for the whole journey is :

Here same distances are covered at different speeds.

∴ Average speed =		2xy		kmph
		x + y

=		2 × 36 × 45		kmph
		(36 + 45)

=	2 × 36 × 45	= 40 kmph
	81