Acme corp has outstanding bonds with a coupon rate of 5% and a current yield of 4.6%. the estimated cost on their preferred stock is 4.8%. it is estimated that the firm will need to have a return of at least 7.2% on any retained earnings that they use for capital investment. if the firms capital consists of $2.8 million in bonds $1.2 million in preferred stock and $16 million in retained earnings, estimate Acme's cost of capital. assume that the firms tax rate is 30% . show your work.