A 5.20 g bullet moving at 672 m/s strikes a700 g wooden block at rest on a

Question:

A 5.20 g bullet moving at 672 m/s strikes a700 g wooden block at rest on a frictionless surface. The bullet emerges, traveling in the same direction with its speed reduced to 428 m/s.
(a) What is the resulting speed of the block?
(b) What is the speed of the bullet-block center of mass?