Flotation costs and the cost of debt In March of $2020$ PepsiCo, Inc. $($PEP$)$ sold $$750$ million worth of $30-$year $4\mathrm{.}75\%$ coupon bonds that pay semi$-$annual interest. At the time the bonds were issued, the market paid $$994\mathrm{.}51$ per bond and the flotation cost was $$17\mathrm{.}48$ per bond. Pepsi's corporate tax rate is $21\%.$

a$.$ Ignoring flotation costs, what is Pepsi's before$-$tax and after$-$tax costs of debt?

b$.$ Considering flotation costs, what is Pepsi's before$-$tax and after$-$tax costs of debt?