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 were 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

One car has speed $=27km/h$

Other has the speed$=18km/h$

According to the problem, speed of first car$=18km/h$

Speed of second car$=27km/h$

$\therefore$ Relative speed of each car with respect to each other$=18+27=45km/h$

Distance between the cars$=36km$

$\therefore$ Time of meeting the cars $\left(t\right)=\frac{Distancebetweenthecar}{Relativespeedofcars}=\frac{36}{45}=\frac{4}{5}h=0.8h$

During this time period, Bird will continue to move from one car to another.

Speed of the bird$\left(v_b\right)=36km/h$

Distance covered by the bird $=v_b\times t=36\times 0.8=28.8km$