A train P travelling at a speed of 15 m/s is able to cross a platform of 200 meter length completely in 30 seconds. Approximately how long will it take train P to cross a man who is coming towards the train on his bike at a speed of27 km/h? [Note: Ignore the length of the bike.]
Answer & explanation
Correct answer: option 2
Length of train = X km/h
Distance = Speed × Time
= 15 × 30 = 450 m
Total Distance = Length of train + Length of platform
450 = 200 + X
X = 450 - 200
X = 250 m
Time taken by train to cross a men on bike with speed = 27 km/h
27 km/h = 27 × \(\frac{5}{18}\) m/sec = \(\frac{15}{2}\) = 7.5 m/sec
Relative speed = 15 + 7.5 = 22.5 m/sec
( When moves in same direction )
Time = \(\frac{250}{22.5}\)
= 11.1 sec