A particle A of mass m initially at rest slides down a height of 1.25 m on a frictionless ramp, collides with and sticks to an identical particle B of mass m at rest as shown in the figure.Then, particles A and B together collide elastically with particle C of mass 2m at rest. The speed of particle C after the collision with combined body (A + B) would be (Take, g=10ms-2)