# Running laps

Alvin, Calvin and Melvin are running laps around a track. Alvin runs a lap every $$4$$ minutes, Calvin runs a lap every $$6$$ minutes and Melvin runs a lap every $$9$$ minutes. If they start off at the same point, how many minutes will it take before all three of them are back at the starting point?

Details and assumptions:
- A lap of the track refers to 1 complete round, back to the starting point.

×