Answer:
21d +25 ≤ 115
Explanation:
Jim's cost will be ...
... 21.00·d + 0.10·250 = 21d +25
He wants his cost not to exceed his budget, so ...
... 21d +25 ≤ 115
_____
The solution is ...
... 21d ≤ 90 . . . . subtract 25
... d ≤ 90/21 ≈ 4.3
so Jim can rent the car a maximum of 4 days.