Mrs. Mendoza had 3 boxes of rocks. She gave 6 rocks away from each box. She now has 30 rocks left. How many rocks were in each box?

16 rocks

Step-by-step explanation:

First, find how many rocks she gave away

She had 3 boxes, and gave 6 away from each, so we can add 6, 3 times, or multiply 3 times 6.

6+6+6=18

6*3=18

She gave 18 rocks away. After she gave them away, she had 30. So, we can add 18 and 30 to find how many she had before she gave any away.

18+30=48

She had 48 rocks, and she had 3 boxes. So, we can divide 48 by 3 to find how many were in each box.

48/3=16

Each box had 16 rocks