By either long or synthetic division, it's easy to show that

The quartic will be exactly divisible by

when the numerator of the remainder term vanishes, or for those values of

such that

I'm not sure how to count the number of solutions (software tells me it should be 80), but hopefully this is a helpful push in the right direction.
The graph shows that the fee caps at 21 days. If the fee was the same today as it was yesterday, that means she must be at least 22 days late as it is the first day the fee is the same as the day before.
3(x+1) = regular cheese burger
Answer: 50 cubic feet
Explanation:
Volume= length•width•height
V = 5ft • 2ft • 5ft = 50
V= 50 cubic feet