A race with three cars
Three cars A, B and C standing at the same starting line. A start the first with 30km/h. Two minutes later, B start going with 40km/h. Three minutes after B started, C also start with a speed of 60km/h. When B catch A at a point, A increase the speed by 15km/h.
When C catch A at a point, how many kilometers will be it far from the starting point?