08.11.12:

SOLUTION:

18

 Assume that initial there were 3*X bullets. So they got X bullets each after division. All of them shot 4 bullets. So now they have (X - 4) bullets each. But it is given that, after they shot 4 bullets each, total number of bullets remaining is equal to the bullets each had after division i.e. X

Therefore, the equation is 3 * (X - 4) = X

3 * X - 12 = X

2 * X = 12

X = 6

Therefore the total bullets before division is =3*X=18