To find how long it will take for the two trains to be 250 kilometers apart, we can use the concept of relative speed. Since the trains are traveling in opposite directions, their speeds will add up.

1. The speed of the first train = 60 km/h.
2. The speed of the second train = 65 km/h.

The combined speed of both trains is: $60 \, \text{km/h} + 65 \, \text{km/h} = 125 \, \text{km/h}.$

Now, we can use the formula for time: $\text{Time} = \frac{\text{Distance}}{\text{Speed}}.$

In this case, the total distance is 250 kilometers, and the combined speed is 125 km/h: $\text{Time} = \frac{250 \, \text{km}}{125 \, \text{km/h}} = 2 \, \text{hours}.$

So, it will take 2 hours for the two trains to be 250 kilometers apart.

Would you like further details or have any questions?

---

Here are 5 related questions to deepen your understanding:

1. What would happen if one train increased its speed by 10 km/h?
2. How far would each train have traveled after 2 hours?
3. What would be the time if the total distance was 500 kilometers?
4. How would the result change if the trains were traveling in the same direction?
5. What if one train started 30 minutes later? How would that affect the time?

Tip: When objects move in opposite directions, always sum their speeds to find the relative speed.