Question

A bus covers 90 km in 2.5 hours how much time is required to cover 30 km with the same speed

Answer 1

distance is directly proportional to time taken keeping the speed same(otherwise use distance = speed x time)

Therefore, as distance decreases time also decreases when the speed is same.

Here, distance decreases by 1/3rd there fore time also decreases by 1/3rd

Therefore, time taken is 2.5/3 hours which is,  0.83 hours

Answer 2

Distance ,d=90km

Time ,t=2.5hr

Speed ,S=d/t

=> s=90/2.5

=> s=36km/hr

Speed remains same i.e.,s=36km/hr

Distance to be covered ,d=30km

As s=d/t , t=d/s

=> time ,t=30/36

=> t=0.834 hr