Question

Two Delhi bound trains leave from Bhubaneswar
at 8 PM and 10 PM respectively. If the two trains
move a 100 km and 120 km per hour respectively
and follow the same route, then at what distance
from Bhubaneswar are they going to meet?
(1) 1500
1200
(3) 1000 (4) 800
(5) 600​

Answer 1

Correct Question :-

Two delhi bound trains leave from Bhuvneshwar at 8 pm and 10 pm respectively. if the two trains move at a speed of 100km/hr and 120km/hr respectively and follow the same root, then at what distance from Bhuvneshwar are they going to meet?

Solution :-

Since the trains left with a gap of 2 hours. And they're moving in the same direction. So let's find the distance travelled in 2 hours by train A.

⇒ Distance = Speed × Time

⇒ d = 100 × 2

⇒ d = 200 km

At the time the train A reaches a point which is 200 km away from Bhuvneshwar, train B leaves from Bhuvneshwar.

Now, The distance b/w them is 0.

Let's find the relative velocity of train B w.r.t train A,

⇒ Rel. velocity(B/A) = 120 - 100

⇒ Rel. velocity(B/A) = 20 km/hr

Let us find the time after which the train B will meet train A.

⇒ Distance = Speed × Time

⇒ 200 = 20 × Time

⇒ Time = 10 hours

The distance at which they meet is the distance travelled by train A in 12 hours (2 hours gap)

⇒ Distance = Speed × Time

⇒ Distance = 100 × 12

⇒ Distance = 1200 Km

Hence, the train would meet at 1200 km from Bhuvneshwar.