A man cycling along the road noticed that every 6 minutes a bus overtakes him and every 2 minutes he meets an oncoming bus. If all buses and the cyclist move at a constant speed, what is the time interval between consecutive buses?
Choose one:  A) 3 minutes  B) 6 minutes  C) 8 minutes  D) 9 minutes  E) 10 minutes

Rationale: "let ' s say the distance between the buses is d . we want to determine interval = \ frac { d } { b } , where b is the speed of bus . let the speed of cyclist be c . every 6 minutes a bus overtakes cyclist : \ frac { d } { b - c } = 6 , d = 6 b - 6 c ; every 2 minutes cyclist meets an oncoming bus : \ frac { d } { b + c } = 2 , d = 2 b + 2 c ; d = 6 b - 6 c = 2 b + 2 c , - - > b = 2 c , - - > d = 6 b - 3 b = 3 b . interval = \ frac { d } { b } = \ frac { 3 b } { b } = 3 answer : a ( 3 minutes ) ."
Answer: A