Flora has 5 boxes that increase in size. In the first box she packs 4 books. In each box after that, she packs 3 more books than the box before. How many books does Flora pack in the last box?

Flora could pack 16 books into the last box.

Step-by-step explanation:

In order to find that, take the amount from the first box and then add 3 for every subsequent box. Since we are moving 4 boxes, add 3 four times.

4 + 3 + 3 + 3 + 3 = 16