A man travelled a distance of 80 km in 7 hrs partly on foot

A man travelled a distance of 80 km in 7 hrs partly on foot at the rate of 8 km per hour and partly on bicycle at 16km per hour. The distance travelled on the foot is

Journey on foot = x km
Journey on cycle = (80 – x) km

∴	x	=	80 − x	= 7
	8		16

⇒	2x + 80 − x	= 7
	16

⇒ x + 80 = 16 × 7 = 112
⇒ x = 112 - 80 = 32 km.

Second Method :
Here, x = 80, t = 7
u = 8, v = 16

Time =		vt − x
		v − u

=		16 × 7 − 80
		16 − 8

=		112 − 80
		8

=	32	= 4 hrs
	8

Distance travelled
= 4 × 8 = 32 kms