A travels at 40 kmph. B travels at 60 kmph. They are travelling towards each…

When two travellers start moving towards each other at the same moment, the time until they meet is the same for both of them. In that common time, each covers a distance equal to their own speed times the time, so the gap between the distances they cover equals the difference of their speeds times that same time.

Application:

1. Let t be the time (in hours) taken for A and B to meet.

2. In time t, A covers 40t km and B covers 60t km.

3. B covers 120 km more than A, so 60t − 40t = 120.

4. Simplifying, 20t = 120, so t = 6 hours.

5. Total distance = A's distance + B's distance = 40 × 6 + 60 × 6 = 240 + 360 = 600 km.

Cross-check: The two travellers close the gap between them at a combined speed of 40 + 60 = 100 kmph, so a 600 km total should take 600 ÷ 100 = 6 hours — matching the time found above. Also, B's distance minus A's distance is 360 − 240 = 120 km, exactly the lead stated in the question, confirming the total distance of 600 km.