Question

Two trains $A$ and $B$, each of length $100\, m$, are running on parallel tracks. One overtakes the other in $20\, s$ and one crosses the other in $10\, s$. The velocity of trains are :-

• A. 5 m / s , 5 m / s
• B. 10 m / s , 15 m / s
• C. 15 m / s , 5 m / s
• D. 15 m / s , 30 m / s

Answer 1

Answer: (C)

If $v_{1}$ and $v_{2}$ are the velocities, then
$\left( v _{1}- v _{2}\right) \times 20=(100+100)$ ...(i)
and $\left( v _{1}+ v _{2}\right) \times 10=(100+100)$ ...(ii)
After solving above equations, we get
$v_{1}=15\, m / s$ and $v _{2}=5\, m / s$