Durga walks 5 km from her home to school in 60 minutes,

Durga walks 5 km from her home to school in 60 minutes, then bicycles back to home along the same route at 15 km per hour. Her sister Smriti makes the same round trip, but does so at half of Durga’s average speed. How much time does Smriti spend on her round trip ?

Durga’s average speed =		2xy		kmph.
		x + y

=		2 × 5 × 15		kmph
		20

=	15	kmph
	2

Distance of School = 5 km.

∴ Required time = 2		5		hours
		15/4

=		2 × 5 × 4		hours
		15

=	8	hours
	3

=		8	× 60		minutes
		3

= 160 minutes