Inelastic Collision With External Impulse

A 0.15 kg bullet is fired horizontally into a 5.0 kg wooden block initially at rest on a frictionless surface. The bullet embeds in the block. During the collision, a 20 N external horizontal force acts on the block for 0.01 s in the direction of the bullet’s motion. Immediately after the collision, the combined system has a speed of 3.0 m/s. What was the initial speed of the bullet?