Question

Two train 126 m and 114 m long are running opposite directions, one at the rate of 30 kmph another one at 42 kmph. From the moments they will cross each other in

• A. 10 sec
• B. 11 sec
• C. 12 sec
• D. 13 sec

Answer 1

The correct option is C 12 sec

$\text{Relative speed}=(30+42)kmph=72kmph=(72\times \frac{5}{18})m/sec=20m/sec\text{Distance covered in crossing each other}=(126+114)m=240m.\text{Required time}=\left(\frac{240}{20}\right)sec=12sec.$