A hunter on a frozen, essentially frictionless pond uses a rifle that shoots 4.20-g bullets at 965

Question:

A hunter on a frozen, essentially frictionless pond uses a rifle that shoots 4.20-g bullets at 965 m/s. The mass of the hunter (including his gun) is 72.5 kg, and the hunter holds tight to the gun after firing it Find the recoil velocity of the hunter if he fires the rifle
(a) Horizontally and
(b) At 56.0 above the horizontal.