To determine the time at which the two trains will pass each other, we can calculate the time it takes for them to cover the combined distance of 900 kilometers.
Let's denote the time it takes for the trains to meet as t hours.
The distance covered by the first train in t hours can be calculated using the formula:
Distance = Rate × Time
For the first train: Distance = 70t km
Similarly, the distance covered by the second train in t hours is:
Distance = 90t km
Since the total distance covered by both trains is 900 kilometers when they meet, we can set up the following equation:
70t + 90t = 900
Combining like terms, we get:
160t = 900
To find t, we divide both sides of the equation by 160:
t = 900 / 160 = 5.625 hours
Now that we know the time it takes for the trains to meet is 5.625 hours, we can determine the actual time they will pass each other.
The trains left at 7:00 a.m., so we add 5.625 hours to that time:
7:00 a.m. + 5.625 hours = 12:38 p.m.
Therefore, the two trains will pass each other at approximately 12:38 p.m.