Problems on trains in aptitude problems are not just to test your ability to solve the problems on trains and their properties but you can logically resolve many theories using this concept and this is one of the important part while learning aptitude.
A Kilometer/Hour = A(5//18) meter/second.
A meter/second = A(18/5) Kilometer/Hour.
Time taken by a train of length 'l' units to cross a fixed point or pole is equal to the time taken by the train to travel 'l' units.
Time taken by a train of length 'l' units to cross a stationery object of length 'm' units units is equal to the time taken by the train to travel 'l+m' units.
Suppose 2 trains are moving in the same direction with speeds U , V where U > V then their relative speed is U - V .
Suppose 2 trains are moving in opposite directions with speeds U , V then their relative speed is U + V .
If two trains start at same time from points A , B respectively towards each other and after crossing they take a and b sec to reach B, A respectively then
(A's speed)B's speed) = (√b : √a)
( relative speed problems on trains )
1) Suppose 2 trains of lengths a, b are moving with speeds u, v (U>V)respectively then the time taken to cross each other is _________
Distance to cover = length of train a + length of train b = a+b .
Relative speed = (U - V)
Time=(a+b)/(U - V).
Relative speed = (U + V)
Time=(a+b)/(U + V).