A water-balloon launcher with mass 4 kg fires a 0.5 kg balloon with a velocity of 3 m/s to the east. what is the recoil velocity of the launcher?

I think we will use the law of conservation of linear momentum;

M1V1 = M2V2

M1 = 4 kg (mass of the water balloon launcher)

V1=?

M2 = 0.5 kg (mass of the balloon)

V2 = 3 m/s

Therefore; 4 V1 = 0.5 * 3

4V1 = 1.5

V1 = 1.5/4

= 0.375 m/s