A boy walks from his house at 4 km per hr. and reaches his

A boy walks from his house at 4 km per hr. and reaches his school 9 minutes late. If his
speed had been 5 km per hr. he would have reached his school 6 minutes earlier. How far his school from house?

Let time taken to reach school at 4 kmph be x hrs.
Then time taken to reach school

at 5 kmph =		x +	15		hrs
			60

Since, distance is equal.

∴ 4x = 5		x +	15
			60

x =	5	hrs.
	4

Hence, distance between school & house

= 4 ×	5	km = 5 km
	4