A man walks from his house at an average speed of 5 km per

A man walks from his house at an average speed of 5 km per hour and reaches his office 6 minutes late. If he walks at an average speed of 6 km/h he reaches 2 minutes early. The distance of the office from his house is

Required distance of office from house = x km. (let)

Time =	Distance
	Speed

∴ According to the question,

x	−	x	=	6 + 2	=	2
5	−	6	=	60	=	15

⇒	6x − 5x
	30

=	2
	15

⇒	x	=	2
	30		15

⇒ x =	2	× 30 = 4 km.
	15

Second Method :
Here, S₁ = 5, t₁ = 6
S₂ = 6, t₂ = 2

Distance =	(S₁ × S₂)(t₁ + t₂)
	S₂ − S₁

=	(5 × 6)(6 + 2)
	6 − 5

= 30 ×	8	= 4 km.
	60