Please idicate the MAXIMUM as well as the OPTIMAL. A short explanation would be great too. Some people say .94 is the maximum without mentioning the optimal. Some people say .94 is the optimal without mentioning the maximum. Very confused please help.

3. e-Five Corp. does not presently offer a cash discount and sells on net 30 terms. However, the firm would like to offer a cash discount for payments made on day 10 to retain its customers as many of the firm's competitors have begun to sell on terms of 1.5/10, net 30. Assuming the firm's cost of funds is 17%, what is the maximum cash discount the firm can offer? What is the optimal discount? (Assume no change in sales)