The following questions are accompanied by two statements (i) and (ii). You have to determine which statement(s) is/are necessary/sufficient to answer the question.

Find out the length of train X given that speed of train X is 20 m/sec.
I. Train X crosses another train Y moving in opposite direction in 6 sec and the speed of train Y is 50% more than the speed of train X.
II. Length of train Y is 50% less than length of train X.

Correct option is A

Speed of train X = 20 m/sec
Let length of train X be x m
From II
length of train Y = 0.5 x m
From I
Speed of train Y = 20 × 1.5 = 30 m/sec
From I & II
(x+0.5x)/6=30+20
x = 200 m