An analysis of a firm’s sales activities indicates that a number of profitable sales are lost each year because the firm cannot deliver same of its products quickly enough. By investing an additional $20,000 in inventory it is believed that a firm will realize $1000 more in before-tax profits in the first year. In the second year, before-tax extra profit will be $1500. profits for subsequent years are expected to continue to increase on a $500-per-year gradient. The investment in the additional inventory may be recovered at the end of a 4- year analysis period simply by selling it and not replenishing the inventory. Compute:  The before tax rate of return  The after-tax rate of return assuming an incremental tax rate of 39%