Sum of the length of two trains P and Q is 330 . The ratio of the speeds of P and Q is `5 : 8` . Ratio between time to cross an electric pole by P and Q is `4 : 3` . Find the difference in the length of two trains .

Options

A. 50
B. 30
C. 40
D. 75

Answer

B

Explanation

Sum of length of train = 330
`l_(1) + l_(2) = 330`
`S_(A) : S_(B) = 5 : 8`
Let speed be 5x and 8x
And time taken to cross pole be 4y , 3y
So ,
`5x xx 4y + 8x + 3y = 330`
44xy = 330
xy = 7.5
`l_(1) - l_(2) = 2xy - 20 xy `
= 4xy
`implies 7.5 xx 4`
`implies 30`