Question

Two trains $121$ and $99m$ in length respectively are running in opposite directions, one at the rate of $40km$ and the other at the rate of $32km$ an hour. In what time will they be completely clear of each other from the moment they meet?

• A. $110seconds$
• B. $99seconds$
• C. $88seconds$
• D. $11seconds$

Answer 1

The correct option is D $11seconds$

Time to cover $(121+99)$, i.e., $220$ metres at the rate of $(32+40)$, i.e., $72km$.
$=\frac{220}{(72\times \frac{5}{18})}=11second$ .