Question

A bird is tossing (flying to and fro) between two cars moving towards each other on a straight road. One car has speed of 27 km h^-1 while the other has the speed of 18 km h^-1. The bird starts moving from first car towards the other and is moving with the speed of 36 km h^-1 when the two cars separated by 36 km. The total distance covered by the bird is

• A. 28.8 km
• B. 38.8 km
• C. 48.8 km
• D. 58.8 km

Answer 1

Answer: (A)

28.8 km

Answer 2

Velocity of car A, $V_{A} = + 27kmh^{- 1}$

Velocity of car B $V_{B} = - 18kmh^{- 1}$

Relative velocity of car A with respect to car B

$= V_{A} - V_{B} = + 27kmh^{- 1} - ( - 18kmh - 1)$

$= 45kmh^{- 1}$

Time taken by the two cars to meat

$= \frac{36km}{45kmh^{- 1}}0.8h$

Thus, distance covered by the bird

$= 36kmh^{- 1} \times 0.8h = 28.8km$