Question

a train leaves X at 7am and reaches Y at 11am. another train leaves Y at 9 am reaches X at 12.30pm .at what time they cross each other ?​

Answer 1

Answer:

9:24 am

Step-by-step explanation:

Let the distance between station A and station B is x km.

Given first train starting from A will take 4 hours to cover x km and the second train starting from B takes 3.5 hours to cover the x km.

Therefore, speed of the train is

4

x

km/hr and

2

7

x

or

7

2x

km/hr respectively.

Let both the train meet t hours after 8 am.

Then first train (starting from A) would have travelled (t+1) hours whereas the second train (starting from B) would have travelled t hours. Therefore, distance travelled by them would be

4

x(t+1)

km and

7

2xt

km respectively.

Clearly, when both the trains met the distance travelled by them will be x km.

Therefore,x = 4

x(t+1)

+

7

2xt

or, 1=

4

t+1

+

7

2t

or, 28=7t+7+8t

or, t=

15

21

hours or

5

7

hours or 1 hour and 24 minutes

Therefore, the trains will met at 9:24 am.