Stations A and B are 1000 km apart. A train leaves A for B at 40 km/h, and at the same moment another train leaves B for A at 60 km/h. How far from A will they meet?

Introduction / Context:
For two objects moving toward each other, the meeting point divides the total distance in the ratio of their speeds (or equivalently, each covers distance = speed * common time). Using either method gives the same result cleanly and quickly.

Given Data / Assumptions:

• Total separation = 1000 km.
• Speeds: A→B = 40 km/h, B→A = 60 km/h.

Concept / Approach:
Since they start together, time to meet is the same for both. Solve by proportional division: the distance from A will be (speed from A / sum of speeds) * total distance.

Step-by-Step Solution:

Verification / Alternative check:
Common meeting time = 1000/100 = 10 h; A’s train covers 40 * 10 = 400 km, B’s covers 600 km—sums to 1000 km.

Why Other Options Are Wrong:
350/300/525 km do not match the 40:60 ratio or the equal-time product.

Common Pitfalls:
Using difference of speeds (that is for relative speed in time calculation) to split distances; here use ratio or equal time logic.

Final Answer:
400 km