Find the time taken by a train 750 m long to cross a platform twice its length at a speed of 81 km/h.

Correct option is C

Given:

Length of first train =750m

Length of platform =2 times of train

Speed of train = 81km/hr

Formula Used:

Time =$$\frac{Distance}{Speed}$$​​

Solution:

Length of platform = $$2 \times 750 =1500m$$​​

Distance to cross = Length of first train + Length of platform   = 750 +1500 =2250m

Speed  in m/sec = $$81 \times \frac{5}{18} = \frac{45}{2}=22.5 \ m/sec$$​​

Time taken to cross platform = $$\frac{2250}{22.5} = 100 \ seconds$$​​