17. Examples 12-2 and 12-3 in this chapter concern a decision between the same two mutually exclusive alter-

natives under identical conditions, except for the corporation's marginal tax rate. In Example 12-2, where the marginal tax rate was 40 percent, the conclusion was to accept Alternative 1. In Example 12-3, where the marginal tax rate was 20 percent, the conclusion was to accept Alternative 2.

Determine the marginal tax rate at which the two alternatives would be economic equivalents; that is, they would "break even" and generate the same excess after-tax payoff over after-tax cost. Your answer should be based on all of the conditions and assumptions as stated in Examples 12-2 and 12-3.