Question

Travelling at 4÷ 5 th if his usual speed ,a man is 15 minutes late . His usual time to cover the same distance is ?

Answer 1

let the usual speed be v

let the usual time be t
and the distance be d

Since distance =speed×time
d=(4/5)v×(t+15)
d/v=(4/5)×(t+15).....1st

Now d/v=t
Putting this value of d/v in 1st
t=(4/5)×(t+15)
t=(4/5)t+12
t/5=12
t=60minutes

Answer 2

Answer:1 Hour

Step-by-step explanation: New speed=4/5 of the usual speed

New time taken =5/4 of usual time

So(5/4 of the usual- time usual time )=15 minutes

1/4 of usual time =15×4=60 minutes

So,60 minutes=1 Hour