What way of calculating ROI makes it easiest to compare investments?

Don’t give me to many notifications because it will cause you to lose alot of points

Information on gerken power co., is shown below. assume the company’s tax rate is 40 percent. debt: 9,400 8.4 percent coupon bonds outstanding, $1,000 par value, 21 years to maturity, selling for 100.5 percent of par; the bonds make semiannual payments. common stock: 219,000 shares outstanding, selling for $83.90 per share; beta is 1.24. preferred stock: 12,900 shares of 5.95 percent preferred stock outstanding, currently selling for $97.10 per share. market: 7.2 percent market risk premium and 5 percent risk-free rate. required: calculate the company's wacc. (do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) wacc %

Why should managers invest any excess cash