Variable Cost and Additional Customers

Question4:
What closing time should Citywide Spirits Shoppe choose to maximize profits?
Through the Attachment: (Evening time)
Contribution Margin = average purchase revenue-average purchase cost
= $30.52-$23.25 = $7.27 per customer per purchase
Average numbers of customer: (Attachment 2)

close time averge customers
Time
Total customer
10pm
10.18
10pm~11pm
12
11pm
10.16
10pm~12pm
21
12pm
10.08
10pm~1am
27
1am
9.71
10pm~2am
32
2am
9.4
10pm~3am
36
3am
9.06
10pm~4am
39
4am
8.71

1. Average profit for the additional hour from 10pm to 12pm = contribution margin*average customers*360 business days per year - $20 clerks salary per hour*360 days
2. Average profit for the additional hour from 12pm to 4am = contribution margin*average customers*360 business days per year - $30 clerks salary per hour*360 days
3. Real profit for the additional hour from 10pm to 12pm = contribution margin*real fact customers*360 business days per year - $20 clerks salary per hour*360 days
4. Real profit for the additional hour from 12pm to 4am = contribution margin*real fact customers*360 business days per year - $30 clerks salary per hour*360 days
5. Total profit before midnight= total numbers of customer*contribution margin*360days - $20 clerks per hour*total hours before midnight*360 days
6 Total profit before midnight= total numbers of customer*contribution margin*360days - $20 clerks per hour*total hours before midnight*360 days - $30 clerks per hour*total hours after midnight*360 days

average customer profit real customer profit Time
Total profit
10pm~11pm
19390.75
10pm~11pm
24206.4
10pm~11pm
24194.33
11pm~12pm
19181.38
11pm~12pm
18961.94
10pm~12pm
40540.08
12pm~1am
14613.01
12pm~1am
10129.55
10pm~1am
45437.25
1am~2am
13792.23
1am~2am
7513.361
10pm~2am
47718.22
2am~3am
12902.72
2am~3am
4897.166
10pm~3am
47383.00
3am~4am
11987.05
3am~4am
2280.972
10pm~4am
44431.58

Based on the question of