A train passes two bridges of lengths 700 m and 300 m in 100 seconds and 60 seconds respectively. The length of the train is

Question: A train passes two bridges of lengths 700 m and 300 m in 100 seconds and 60 seconds respectively. The length of the train is

Solution:
Let the length of the train be x m
Speed s = (x + 700)/100.................(1)
Speed s = (x + 300)/60................(2)

Now
(x + 700)/100 = (x + 300)/60
(x + 700)/5 = (x + 300)/3
5x + 1500 = 3x + 2100
5x - 3x = 2100 - 1500
2x = 600
x = 300