Two walkers meet: when and how far?

Two people start 3000 m apart and walk toward each other at 60 m/min and 40 m/min. When do they meet?

Step-by-step

1. 60 + 40 = 100
   Moving toward each other, the relative speed is the sum of the speeds
2. 3000 ÷ 100 = 30
   Time to meet head-on = distance ÷ relative speed

Why it works

When two objects move toward each other, they close the gap at the sum of their speeds. Dividing the total distance by that sum gives the meeting time — no need to track each person separately.

Common mistakes

• Adding the distances instead of the speeds.
• Using the difference of the speeds (that is the catch-up case, not the meeting case).

Related

vertical-throw conveyor-belt meeting-hikers-3200m-85-75