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 $ 1,400,000 510,000 890,000 610,000 $ 280,000 $ 875,000 At the beginning of this year, the company has a $175,000 investment opportunity with the following cost and revenue characteristics: Sales Contribution margin ratio Fixed expenses $ 280,000 50 of sales $ 98,000 The company's minimum required rate of return is 15%. Required: 1. What is last year's margin? Margin %