A train x running at 74 km/h crosses another train y running at 52 km/h in the opposite direction in 12 seconds. If the length of y is two-thirds that of x, then what is the length of y (in m)?
Answer & explanation
Correct answer: option 2
Relative speed = ( 74 + 52 ) = 126 km/h
126 km/h = 126 × \(\frac{5}{18}\) m/sec = 35 m/sec
Time taken = 12 sec
Distance = Speed × Time
Distance = 35 × 12 = 420 km
According to question ,
Ratio of length of x : y
3 : 2
5R = 420 km
1R = 84 km
Length of train y = 2R = 2 × 84 = 168 km
So , length of train y is 168 km.