Question

A train leaves Delhi at 6:00 am and reaches Haridwar at 10:00 am. Another train leaves Haridwar at 8:00 am and reaches Delhi at 11:30 am. At what time the trains meet?

Answer 1

Suppose distance between Delhi and Haridwar is 28 km.
Then speed of first train = 28/4= 7 kmph
The speed of 2nd train = 28/3.5= 8 kmph

If trains met after t hours from 6 AM, then
So, the distance travelled by the first train is $=7tkm$
Distance travelled by the second train is $=8(t-2)km$ as it start as 8 a.m .

So, total distance, $7t+8\times (t-2)=28$
$15t=44$
$\Rightarrow t=\frac{44}{16}$ hours.
$=2\frac{12}{16}$
$t=2$ hrs 56 mins.
So the trains meet at 8: 56 am