I would be glad to help you, however what is the function?
Answer: About 45.
Step-by-step explanation: There's always a pattern in these kinds of questions, you can see for 9th to 13th August, the number has always been between 20 to 40. And since on 13th August the graph is on a rise again, it would be around 45. 90 is just not realistic considering there's only an increase of around 5-10 tickets every day.
The number of situps form an AP with first term (a) = 17 and common difference (d) = 4
Tn = a + (n - 1)d
T12 = 17 + (12 - 1) x 4 = 17 + 11(4) = 17 + 44 = 61
Therefore, she will do 61 situps on day 12.
The answer should be $31.80.
Hope this helped!!!:)