Question

A train leaves Pune at 7:30 am and reaches Mumbai at 11:30 am. Another train leaves Mumbai at 930 am and reaches Pune at 1:00 pm. Assuming that the two trains travel at constant speeds, at what time do the two trains cross each other?

• A. 10:20 am
• B. 11:30 am
• C. 10:26 am
• D. data not sufficient

Answer 1

The correct option is B 11:30 am

Let distance b/w Pune and Mumbai be l speed of $1^{st}train=\frac{l}{4}$
$2^{nd}train=\frac{l}{3_2^1}$
$=\frac{2l}{7}$
distance covered by $1^{st}$ train in 2 hours $=\frac{l}{4}\times 2=\frac{l}{2}$
at 9:30 relative distance to be covered $=\frac{l}{2}$
Let they meet at time t
$\frac{l}{2}=(\frac{l}{4}\times t)+\frac{2l}{7}t$
$\frac{l}{2}=t\left(\frac{7+8}{28}\right)\Rightarrow t=\frac{14}{15}hoursor56$
$\therefore 9:30+56mins=10:26$