Answer:
8 boxes.
Explanation:
We have to find out how many times 6 goes into 45.
45/6 = 7.5
Unfortunately, you can't have half a box. To correct this and be able to find the fewest amount of boxes, you simply round to the nearest whole number.
In this case, since the max amount of shirts that can fit in a box is 6, you must round up.
7.5 rounded up is 8.
The fewest amount of boxes you need is 8.