Assume Nail Mania advertises in the local newspaper. Each day it advertises costs $100. Over the past several months, Nail Mania has conducted market research and developed the following information
Number of days advertised per week Number of customers per week
0 100
1 200
2 290
3 355
4 375
5 390
6 400
7 400
If the net revenue (payments less cost of goods sold) is $5, how many days of advertising should Nail Mania buy each week?