Required information [The following information applies to the questions displayed below] Westerville Company reported the following results from last year's operations: Sales Variable expenses Contribution margir Fixed expenses Net operating income $ 1,400,800 680,000 720,000 440,000 28e,000 Average operating assets875,00 At the beginning of this year, the company has a $300.000 investment opportunity with the following cost and revenue characteristics: $ 488,000 Sales contribution margin ratio Fixed expenses 88% of sales $ 336,0e The company's minimum required rate of return is 15%. Required 1. What is last year's margin