Question

Two boats are moving apart at the speed of 28 km/hr and speed of stream is 3 km/hr, find the sum of speeds of both boats (in km/hr)

1. 25
2. 56
3. 31
4. Cannot be determined
5. None of these

Answer 1

Correct Answer - Option 2 : 56

Given:-

Relative speed of boats when moving apart = 28 km/hr

Stream speed = 3 km/hr

Formula:-

Speed = Distance/Time

Downstream speed = u + v

Upstream speed = u – v

u and v are boat and stream speeds.

Calculation:-

Speed of boat 1(assume it is going downstream) = b1 + v

Speed of boat 2 (assume it be going upstream) = b2 – v

Relative speed = 56 = b1 + v + b2 – v = b1 + b2

Relative speed when boats are going in opposite direction is independent of stream speed.