Collisions and conservation of momentum involving a block and bullet...?

Question

A bullet of mass 4.5 g is fired horizontally into a 2.4 kg wooden block at rest on a horizontal surface. The bullet stops in the block. The speed of the block immediately after the bullet stops relative to it is 2.7 m/s. At what speed is the bullet fired?

Answer 1

Let the mass of the bullet be m and that of the block M. The speed of the bullet is v and that of the bullet and block V. Then
mv = (M+m)*V
or v = (M+m)*V/m = 1443 m/s