Collin Products received notice of a $21,000 income tax deficiency plus $4,300 interest. The deficiency related to an incorrect method of accounting for business inventory. Compute the after-tax cost of the $4,300 interest payment assuming that:

a. Collin Products is a corporate taxpayer with a 35 percent marginal tax rate.

b. Collin Products is a sole proprietorship owned by Leslie Collin. Leslie's marginal tax rate on her Form 1040 is 39.6 percent.