Question

Two trains, each 100 m long, moving in opposite directions, cross each other in 8 s. If one is moving twice as fast the other, then the speed of the faster train is

Options

• 30 km/h

• 45 km/h

• 60 km/h

• 75 km/h

Answer 1

60 km/h
Explanation:
Let the speed of the slower train be x m/s.
Then, the speed of the faster train = 2x m/s.
Relative speed = (x + 2x) m/s = 3x m/s.

∴ `((100+100))/8=3x`

⇒ 24x = 200

⇒ `x=25/3`m/s

So, speed of the faster train = `50/3`m/s

= `(50/3xx18/5)=60`km/h