Given that train K crosses a pole in 30 seconds and train L crosses the same pole in one minute and 15 seconds.
Let the length of train K be Lk and that of train L be Ll
given that Lk = 3/4 Ll
As the train K and L crosses the pole in 30 seconds and 80 seconds respectively,
=> Speed of train K = sk = Lk/30
Speed of train L = sl = Ll/80
Lk = 3/4 Ll
=> sk = 3/4 Ll/(30) = Ll/40
Ratio of their speeds = sk : sl
= Ll/40 : Ll/80
=> 1/40 : 1/80 = 2 : 1
