一道头晕的manhattan题

evelyn205205

Car B starts at point X and moves clockwise around a circular track at a constant rate of 2 mph. Ten hours later, Car A leaves from point X and travels counter-clockwise around the same circular track at a constant rate of 3 mph. If the radius of the track is 10 miles, for how many hours will Car B have been traveling when the cars have passed each other for the first time and put another 12 miles between them (measured around the curve of the track)?

答案是4π+8.4

各位NN，这道题怎么做哟？
麻烦各位啦~

evelyn205205

求指教啊~

dxt678

设B一共走了X小时，则A走了X-10小时，两车一共行驶距离为一个圆加上12MIL

3(X-10)+2X=2*Pi*10+12

5X=20P+42

X=4P+8.4

evelyn205205

非常感谢！