Don't understand 16d at all really need asap

An inequality is with the >, <, or the = SO, initial one time reservation, you add onto the fee. 75 dollars each time, you pair that with c.
HOW IT SHOULD LOOK:

50(at the start) + 75c(the money charged for each cleaning) ≤ B

THE REASON WHY: the maximum budget is pretty much all you can spend, so the cost of the cleaning, as it says in the LAST LINE should not be over the budget, but can be under so we use the less than or equal to sign.
C is the number of leaning, 75 is the money charged for each cleaning, 50 is the initial cost of joining, and it should be added as part of the money you spent on the cleaning company
and that's it

The letters represent the numbers u don't know yet I don't really know how to explain it (but I know how to write it) so ill give you the answer for the inequality(question to represent the problem) it is simple is 5 plus 75C =B hope this is helpful