Let's imagine that A had one more pie.
Then when packing the pies 5 to a box, there would be *no* remainder.
And when packing the pies 9 to a box, there would be *no* remainder.
That number of pies would be an exact multiple of 5 and 9. Given that 5 and 9 have no factors in common (other than 1), the lowest common multiple is 45.
But any multiple of 45 would also work (45, 90, 135, 180, etc.)
However, that's after we added 1 pie. Remove the 1 extra pie and you have the answer:
45, 89, 134, 179, etc.
Technically any of those work unless there is some restriction (number of pies less than 50, etc.).
Given that the question seems to expect a unique answer, my guess is they wanted you to say 44 pies. But without a restriction, there are technically an infinite number of possible answers.
Possible answers = 44 pies, 89 pies, 134 pies, 179 pies, etc.