Question

25. Train A travelling at 63 kmph can cross a
platform 199.5 m long in 21 seconds. How much
time would train A take to completely cross
(from the moment they meet) train B, 157 m
long and travelling at 54 kmph in opposite
direction in which train A is travelling ? (in
seconds)​

Answer 1

Answer:

Speed of train A = 63 kmph = (63×518)m/sec = 17.5 m/secSpeed of train B = 54 kmph = (54×518)m/sec = 15 m/secIf the length of train A be x metre,thenSpeed of train A = Length of train + length of platformTime taken in crossing ⇒17.5=x+199.521⇒17.5×21=x+199.5⇒367.5=x+199.5⇒x=367.5−199.5⇒168metresRelative speed = ( Speed train A + Speed train B) = (17.5 + 15) m/sec = 32.5 m/secRequired time =  Length of train A + Length of train BRelative speed =(168+15732.5)seconds=10seconds

Step-by-step explanation: