A train travelled at a speed of 35 km/hr for the first 10

A train travelled at a speed of 35 km/hr for the first 10 minutes and at a speed of 20 km/hr for the next 5 minutes. The average speed of the train for the total 15 minutes is

Distance covered =		35 ×	10	+ 20 ×	5		km
			60		60

=		35	+	10		km
		6		6

=	45	km
	6

Total time = 15 minutes

=	1	hour
	4

∴ Required average speed =	Distance covered
	Time taken

=	45	× 4
	6

= 30 kmph