Two blocks with different mass are attached to either end of a light rope that passes over a light, frictionless pulley that is suspended from the ceiling. The masses are released from rest, and the more massive one starts to descend. After this block has descended 1.20 meter, its speed is 3.00 meter per second. If the total mass of the two blocks is 15.0 kilogram, evaluate what is the mass of each block?