Question

Two trains having lengths of 210m and 140m are running at speed of 80 km/h and 150 km/h respectively, in the same direction. The time taken (in minutes) by the faster train, coming from behind, to completely cross the other train is :

• A. 2
• B. 0.3
• C. 0.5
• D. 1

Answer 1

Answer:

B. 0.3

Lengths of trains:

• Train A = 210 m

• Train B = 140 m

Total distance to be covered to completely cross:

$210 + 140 = 350 \text{ m}$

Speeds:

Slower train = 80 km/h

Faster train = 150 km/h

Since they move in the same direction, relative speed:

$150 - 80 = 70 \text{ km/h}$

Convert relative speed to m/s:

$70 \times \frac{5}{18} = \frac{350}{18} \text{ m/s}$

Time taken:

$\text{Time} = \frac{350}{350/18} = 18 \text{ seconds}$

Convert seconds to minutes:

$\frac{18}{60} = 0.3 \text{ minutes}$