IBPS SO Prelims Exam Model Paper 2

Let, length of the platform = x m.
Length of the second train = y m.
Speed of the first train = 20 m/s = 20 ×

18

5

km/hr = 72 km/hr
∴ speed of the second train = (72 - 18) km/hr = 54 km/hr
According to problem,
⇒ 173 + x = 21 × 20
⇒ x = 420 - 173
⇒ x = 247
∴ length of the platform = 247 m
According to problem,
⇒ 247 + y = 15 × 21
⇒ y = 315 - 247
⇒ y = 68
∴ length of the second train = 68 m.