Bob has three sacks of apples and three more apples in his pocket. Each sack contains the same numb?

The only unknown is the number of apples in each sack. 3 apples are in Bob's pocket and there are 3 sacks. Altogether there are 33 apples.

3 (x + 1) = 33 | Divide both sides of the equation by 3
x + 1 = 11 | Subtract from both sides of the equation1
x = 10

So, there are 10 apples in each sack, if, as predefined in the task, each sack contains the same number of apples.

10 in each sack.
You subtract the three extra apples in his pocket to get 30, then divide by the number of sacs to figure out how many was in each sac. 30 divided by 3 equals 10.