Question

A train left Howrah station at 10 A.M. with a speed of 10 m/s. After 2 hours another train with double the speed leaves Howrah station in the same direction. Find at what time the two trains will meet.

1. 1 P.M.
2. 2 P.M.
3. 3 P.M.
4. 4 P.M.
5. 3.30 P.M.

Answer 1

Correct Answer - Option 2 : 2 P.M.

Given:

Speed of first train = 10 m/s 

Speed of second train = Double the speed of first train

Formula:

Distance = speed × time

Speed in m/s to km/h = multiply by 18/5

Calculation:

Speed of first train in km/h = 10 × 18/5 = 36 km/h

Speed of the second train = 2 × 36 km/h = 72 km/h

Let after x hours of starting of second train they meet

Distance covered by first train = (2 × 36) + (36 × x) km = 72 + 36x

Distance covered by second train = (72 × x) km = 72x km

Distance covered by second train = Distance covered by first train

⇒ 72x = 36x + 72

⇒ 72x – 36x = 72

⇒ 36x = 72

⇒ x = 2

After 2 hrs of starting of second train they will meet

∴ The two trains will meet at 2 P.M.