[The following information applies to the questions displayed below.,] Westerville Company reported the following results from last year's operations $1,200,000 320,000 Sales Variable expenses 880,000 640,000 Contribution margin Fixed expenses Net operating income Average operating assets $ 240,000 $ 600,000 This year, the company has a $150,000 investment opportunity with the following cost and revenue characteristics: $240,000 Sales Contribution margin ratio Fixed expenses 50 % of sales $ 84,000 The company's minimum required rate of return is 15%. Required information 0.50 points Required 1. What is last year's margin? argin