Westerville Company reported the following results from last year's operations: Sales Variable expenses Contribution margin Fixed expenses Net operating income Average operating assets $1,600,000 700,000 900,000 660,000 $ 240,000 $1,000,000 This year, the company has a $325,000 investment opportunity with the following cost and revenue characteristics Sales Contribution margin ratio Fixed expenses $520,000 70% of sales $312,000 The company's minimum required rate of return is 15%. Required: 1. What is last year's margin? Margin %