Question

Two trains A and B leave Delhi for Bangalore at 9 am and 9:30 am respectively. Train A
travels at a speed of 120 km/hr while Train B travels at a speed of 150 km/hr. At what
distance from Delhi will the two trains meet?
A 30 km
B 60 km
C 120 km
D 270 km
E 300 km

Answer 1

After 300 km. (E)

Train A which has been started before 30 minutes (1/2 Hour) will have been covered $120 \times \frac{1}{2} = 60 \: km$ before Train B has started.

After this assume that they take t hours to meet each other.

So,
60 + (120×t) = (150×t)
60 + 120t = 150t
60 = 150t - 120t
60 = 30t
2 = t

t = 2 hours.

That mean they will meet at (9:30 + 2:00) = 11:30 a.m.

Distance will be 150 kmph ×2 hours = 300 km.