Two cars A and B, are moving along a straight road in the same direction with velocities of 25 km/hr and 40km/hr respectively. What is the velocity of car B relative to car A?

Given data in this problem can be listed as,

velocity of car A = 25km/hr

velocity of car B = 40km/hr

Since the cars are moving in same direction , relative velocity can be obtained by subtracting their velocities.

therefore,the velocity of car B relative to car A is,

 40km/hr - 25 km/hr = 15 km/hr