A person takes 40 minutes more than his usual time when he covers a distance of 20 km at 5 km/h. If he covers the same distance at 8 km/h, he takes x minutes less than the usual time. What is the value of x?

50

Distance = Speed × Time

Time = \(\frac{Distance }{Speed}\)

= \(\frac{20 }{5}\) = 4 hours

As , time of 4 hours is 40 minute more than usual time .

So , Usual time is 3 hours 20minutes

Now ,

If Speed is 8 km/h

Time = \(\frac{20 }{8}\) = 2 hours 30 minutes

Difference in time = 3 hours 20minutes  - 2 hours 30 minutes  = 50 minutes