Question

A and B starts from a point C towards D with a speed of 40 km/h and 45 km/h respectively, If  A starts at 8 a.m. and B starts at 9 a.m., then at what time will B catch A? 
1. 5 p.m.
2. 8 p.m.
3. 7 p.m.
4. 6 p.m.

Answer 1

Correct Answer - Option 1 : 5 p.m.

Given:

A's speed = 40 km/h

B's speed = 45 km/h

A's starting time = 8 a.m.

B's starting time = 9 a.m.

Concept:

While moving in the same direction the relative speed is the difference of individual speeds.

Formula used:

Speed = distance/time

Calculation:

A's distance in 1 hr = 40 km

Relative speed = 45 - 40 = 5 km/h

Time = 40/5 = 8 hrs

B will catch A at = 9 + 8 = 5 p.m.

∴ The answer is 5 p.m.