The Beta Corporation has an optimal debt ratio of $40$ percent. Its cost of equity capital is $10$ percent, and its before$-$tax borrowing rate

is $7$ percent. Given a marginal tax rate of $30$ percent.

Required:

a$.$ Calculate the weighted$-$average cost of capital.

b$.$Calculate the cost of equity for an equivalent all$-$equity financed firm

Note: Do not round intermediate calculations. Round your answer as a percent rounded to $2$ decimal places.