Two cars start from the same place at the same time at right angles to each other. Their speeds are 54 km/hr and 72 km/hr, respectively. After 20 seconds the distance between them will be:

Solution (By Examveda Team)

54 km/h = 54 × $$\frac{5}{{18}}$$ = 15 m/s
72 km/h = 72 × $$\frac{5}{{18}}$$ = 20 m/s

The distance of BC = 15 × 20 = 300 m
The distance of AB = 20 × 20 = 400
$${\text{AC}} = \sqrt {{{400}^2} + {{300}^2}} = 500$$