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 20 kmph. Another train starts from B at 8 a.m. and travels towards A at a speed of 25 kmph. At what time will they meet?
9 a.m.
10 a.m.
10.30 a.m.
11 a.m.
Explanation:
Suppose they meet $ x $ hours after 7 a.m.
Distance covered by A in $ x $ hours = 20$ x $ km.
Distance covered by B in $\left( x - 1\right)$ hours = 25$\left( x - 1\right)$ km.
$\therefore 20 x $ + 25$\left( x - 1\right)$ = 110
$\Rightarrow 45 x $ = 135
$\Rightarrow x $ = 3.
So, they meet at 10 a.m.