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 margin Fixed expenses Net operating income Average operating assets $ 1,400,000 720,000 680,000 470,000 $ 210,000 $ 875,000 At the beginning of this year, the company has a $350,000 investment opportunity with the following cost and revenue characteristics: Sales $ 560,000 Contribution margin ratio Fixed expenses 70% of sales $ 336,000 The company's minimum required rate of return is 15%. Required: 1. What is last year's margin? Margin %