Question

Mohan walking at a speed of 20 km/hr reaches his office 1 hour late. Next time he increases his speed by 5 km/hr, then he reaches his office 30 minutes early. What is the distance of his office from his house?

Answer 1

Let distance between office and house is x km. and accurate office time taken to reach the office is t.

a/c to question, Mohan walking at a speed of 20 km/h rashes office 1 hour late.

so, t + 1 = x/20 ......(1)

when Mohan increases his speed 5km/h, then he reaches his office 30min or 1/2h early.

so, t - 1/2 = x/(20 + 5) = x/25 ....(2)

or, from equations (1) and (2),

(t + 1) - (t -1/2) = x/20 - x/25

or, 3/2 = x/100

or, x = 150 km

hence, distance between office and house is 150km