Train A 120 m long is moving with 20 m/s. Train B 130 m long is moving with 30 m/s in opposite direction. In what time, train B will cross train A?

Train A 120 m long is moving with 20 m/s. Train B 130 m long is moving

1.	Train A 120 m long is moving with 20 m/s. Train B 130 m long is moving with 30 m/s in opposite direction. In what time, train B will cross train A?
Answer» 65 365 385 None of these Solution :Speed of train `A v _(A) = 20 m//s` Speed of train `B v _(B) = 30 m//s` If both trains moving in opposite, then relative speed, `v = v _(A) +v_(B)` `=20+30 =50m//s` Total LENGTH of both trains, ` l = (120 +130) m = 250 m` TIme TAKEN to cross, `t = (l)/(v) = (250)/(50) =5s` This is not given in options. `therefore ` The correct option is (D).