Question

Two stations A and B are 110 km apart on a straight line. One train starts from A at 7 A.M and travels towards B at a speed of 20 km/hr. Another train starts from B at 8 A.M and travels towards A at a speed of 25 km/hr. At what time will they meet?

• A. 9 A.M.
• B. 10 A.M.
• C. 11 A.M.
• D. 10:30 A.M.

Answer 1

The correct option is B

10 A.M.

We know, Time = $\frac{Distance}{Speed}$

Here, we have to consider the relative speed of two trains $\Rightarrow$ 20 km/hr + 25 km/hr = 45 km/hr (since they are moving in opposite direction)

Here, the distance between them cannot be taken as 110 km as train B didn't start at 7 A.M.

The distance train A would have covered from 7 A.M to 8 A.M will be = $20km/hr\times 1hr=20km$

So, the distance between these two trains will become 110 km - 20 km = 90 km at 8 A.M

So now, the time taken for them to meet = $\frac{90km}{45km/hr}=2hrs$

$\therefore$ They meet 2 hrs after 8 A.M i.e 10 A.M.