Question

A train of length 165 metres overtakes another train of length 135 metres in a minute. If the speed of the faster train is 45 km/hr, then find the speed of the slower train.

• A. 36 km/hr
• B. 40 km/hr
• C. 27 km/hr
• D. 30 km/hr

Answer 1

The correct option is C 27 km/hr

Let the speed of the slower train be S m/s.

Given, speed of the fast train = 45 km/hr =$45\times \frac{5}{18}$m/s = 12.5 m/s

Total distance travelled while overtaking = 165 + 135 = 300 metres

According to the question,

300 = (12.5 – S) × 60

⇒ 5 = 12.5 – S

⇒ S = 7.5 m/s =$7.5\times \frac{18}{5}$km/hr = 27 km/hr.

Hence, option C is the correct answer.