The hunter fires a gun from a moving boat in the direction of its movement. How fast was the boat moving if it stopped

The hunter fires a gun from a moving boat in the direction of its movement. How fast was the boat moving if it stopped after two quick successive shots? The mass of the hunter with the boat is 200 kg, the mass of the charge is 20 g. The velocity of shot and powder gases is 500 m / s.

Given:
M = 200 kg;
m = 20 g = 0.02 kg;
v = 500 m / s.
Find boat speed V.
Decision:
We use this formula MV = mv + mv = 2 mv.
Let us express V.
V = 2v * m / M.
Plug in the known values and get the answer.
V = 2 * 500 * 0.02 / 200 = 0.1 m / s
Answer: 0.1