Do fast don't waste my time so expert first take question and then release it ( if you do that then I will report you )

A stone is dropped at + = 0. A second stone, with 2 times the mass of the first, is dropped from the same point at t = 97 ms, (a) How far below the release point is the center of mass of the two stones at t - 300 ms? (Neither stone has yet reached the ground ) (b) How fast is the center of mass of the two-stone system moving at that time? (a) Number i Units (b) Number i Units