Question

I do not see how to do this problem

One car has twice the mass of a second car, but only half a smuch kinetic energy. when both cars increase their speads by 7.0 m/s, they then have the sam kinetic energy. What were the original speeds of the cars?

Answer 1

supposively the ansswer is 9.9 m/s and 4.9 m/s i do not see how to get these solutions