Question

A train B speeding with 120 kmph crosses another train C, running in the same direction in 2 minutes. If the length of the trains B and C be 100 m and 200 m respectively, what is the speed of the train

• A. 111 kmph
• B. 127 kmph
• C. 123 kmph
• D. 129 kmph

Answer 1

The correct option is A 111 kmph

$\text{Let the speed of train C be}x\text{kmph.}\text{Speed of B relative to C}=(120-x)=\left[\right(120-x)\times \frac{5}{18}]m/sec=\left(\frac{600-5x}{18}\right)m/sec\text{Distance covered}=(100+200)m=300m\therefore \frac{300}{\left(\frac{600-5x}{18}\right)}=120\Rightarrow 5400=120(600-5x)\Rightarrow x=111.$