Question

A car travel from a to b at a constant speed. If its speed were increased by 10 km/h, it would have been taken 1 hour lesser to cover to that distant. It would have taken 45 minute lesser if its speed further increased by 10km/h.The distance between two cities is?

Answer 1

Let,

d = distance between A and B

t = Time taken for normal

v = velocity

d = v t -------(1)

If speed is increased by 10km/h then time taken reduced by 1hr, then d= (v+10) (t -1) ......(2)

If speed is further increased by another 10km/h, time taken decreases by another 45 min. =0.75hrs then

d= (v+20) (t - 1.75)......(3)

solving equations (1), (2) and (3), we get t = 7hrs, v= 60 km/hr distance (d) = 420km