There is a train which leaves point A at 10:00 and will arrive at point B at 11:30.
There is another train which leaves point B at 10:20 and goes to point A.
Both trains have the same speed .
What time does two trains pass each other?
There is another train which leaves point B at 10:20 and goes to point A.
Both trains have the same speed .
What time does two trains pass each other?
Answer
The time of passing each other is in the middle of 10:20 and 11:30 that is at (10:20 + 11:30) / 2 = 10:55.
Then the time will be at 10:20 + 35 minutes = 10:55.
10:55
Solution
Writing a diagram is the best way to resolve this problem.
The time of passing each other is in the middle of 10:20 and 11:30 that is at (10:20 + 11:30) / 2 = 10:55.
<Another solution>
Calculation can also be performed.
When distance of point A and B is set to 90 which comes from 11:30 minute 10:00 = 90 minutes, the speed of a train is set to 90/ 90minutes = 1.
The distance of two train at 10:20 is 90 - 1 × 20minutes = 70.
The time for passing each other is 70/(1+1) = 35 minutes.
When distance of point A and B is set to 90 which comes from 11:30 minute 10:00 = 90 minutes, the speed of a train is set to 90/ 90minutes = 1.
The distance of two train at 10:20 is 90 - 1 × 20minutes = 70.
The time for passing each other is 70/(1+1) = 35 minutes.
Then the time will be at 10:20 + 35 minutes = 10:55.
