Distance

[demoskopico]

A man cycling along the road noticed that every 12 minutes a bus overtakes him while every 4 minutes he meets an oncoming bus. If all buses and the cyclist move at constant speed, what is the time interval between consecutive buses?

5 minutes
6 minutes
8 minutes
9 minutes
10 minutes


how can I approach this kind of distance problems? I still find many difficulties in finding values in case of surpasses, stops, intervals etc...

[kevin]

You are told that the two travel at constant speeds. Can you think in terms of relative velocity? The cyclist (c mph) is travelling a speed of c + b mph relative to oncoming buses ( b mph) and at a speed of b - c relative to buses travelling in the same direction