Two trains start from a certain place on two parallel tracks in the same direction. The speed of the trains are 45 km/hr and 40 km/hr respectively. The distance between the two trains after 45 minutes will be :

A. 2.500 km

B. 2.750 km

C. 3.750 km

D. 3.25 km

Answer: Option C

Solution(By Examveda Team)

Relative speed :
$$\eqalign{ & = \left( {40 - 45} \right) \times \frac{5}{{18}} \cr & = \frac{{25}}{{18}}{\text{ m/s}} \cr} $$
∴ Required distance :
$$\eqalign{ & {\text{ = }}\frac{{25}}{{18}} \times 45 \times 60 \cr & = 3750{\text{ metres or 3}}{\text{.75 km}} \cr} $$