Westerville Company reported the following results from last year's operations: Sales $ 1,750,000 520,000 Variable expenses Contribution margin 1,230,000 880,000 FIxed expenses Net operating income Average operating assets $ 350,000 s 875.000 This year, the company has a $200,000 investment opportunity with the following cost and revenue characteristics Sales $320,000 Contribution margin ratio Fixed expenses 60 % of sales $ 128,000 The company's minimum required rate of return is 20%