Question

A started his morning walk at 6:30 A.M. with a speed of 12 km/h. B started his morning walk at 7:30 A.M. from the same point with the speed of 16 km/h. After how much time B will overtake A?
1. 3
2. 4
3. 5
4. 6

Answer 1

Correct Answer - Option 1 : 3

Given:

A started his morning walk at 6:30 A.M. with a speed of 12 km/h.

B started his morning walk at 7:30 A.M. from the same point with the speed of 16 km/h.

Formula:

Time = Distance/Speed

Relative speed = (v₁ – v₂), when objects run in the same direction.

Where,

v₁ → Speed of first object

v₂ → Speed of second object

Calculations:

Distance cover by A in 1 hour = 12 × 1 = 12

At 7:30 A will cover 12 km and B will start

So, distance between A and B when B starts = 12 km

Relative speed = 16 – 12 = 4 km/h

Required time = 12/4 = 3 hours

∴ After 3 hours B will overtake A