A train running at 50 km/hr, passes a man walking on the platform at 7 km/hr in same direction as that of train in 15 sec. If this train takes 30 seconds to cross the platform then find the length of train (L1) and length of platform (L2)? Answers
A) L1 =179.1 m, L2 = 237.3 m	B) L1 = 150.5 m, L2 = 300 m	C) L1 = 237.3 m, L2 = 179.1 m	D) L1 = 300 m, L2 = 150.5 m	E) None of these
EXPLANATION:   Given: Speed of train = 50 km/hr, time required to cross the platform = 30 sec, time required to cross man standing on platform = 15 sec.   1) Convert km/hr into m/s   - 50 km/hr = 50 x	5/18= 13.88 m/s   - 7 km/hr = 7 x	5/18=1.94 m/s   2) The speed of train relative to man = ( 13.88 – 1.94) = 11.94 m/s ---- (The values are subtracted because the train and man move in same direction)   3) Length of train = (Relative speed x Time)   = (11.94) x (15) = 179.1 m   We know,   Speed =	(L1 + L2)/Time   13.88 =	(L1 + L2)/30 ---- consider L1 as length of train and L2 as length of platform   (L1 + L2) = 416. 4   L2 = 416.4 – 179.1 = 237.3 m   L1 =179.1 m, L2 = 237.3 mNSWER IS L1 =179.1 m, L2 = 237.3 m
<result>A</result>
A train running at 50 km/hr, passes a man walking on the platform at 7 km/hr in same direction as that of train in 15 sec. If this train takes 30 seconds to cross the platform then find the length of train (L1) and length of platform (L2)?