The following data are for the Akron Division of Consolidated Rubber, Inc.: Sales Net operating income Average operating assets Stockholders' equity Residual income $900,000 $ 75,000 $400,000 $ 90,000 $ 30,000 For the past year, the minimum required rate of return was: Multiple Choice O 60.00% O 11.25% O 30.33% O 8.33%