Answer:
c 17
Step-by-step explanation:
You make 23 a day plus 3.60 per sale
Income = 23+ 3.6 s
You want to make at least 84
84 ≤ 23+ 3.6 s
Subtract 23 from each side
84 -23 ≤ 23-23 +3.6s
61 ≤ 3.6s
Divide by 3.6 on each side
61/3.6 ≤ 3.6s/3.6
16.94444 ≤ s
You must make more than 16.94444 sales
But you cannot make part of a sale so
You must make at least 17 sales