A is travelling at 72 km per hour on a highway while B is travelling at a speed of 25 mitres per second. What us the difference in their speeds in mitres per second ?

Answer: Option D

A's speed :
= 72 km/hr
= $$\left(72\times \frac{5}{18}\right)$$  m/sec
= 20 m/sec
B's speed = 25 m/sec
Difference :
= (25 - 20) m/sec
= 5 m/sec