Problem $18-17$ Costs of Borrowing $[$LO$3]$

In exchange for a $$480$ million fixed commitment line of credit, your firm has agreed to do the following:

Pay $2\mathrm{.}4$ percent per quarter on any funds actually borrowed.

Maintain a $3$ percent compensating balance on any funds actually borrowed.

Pay an up$-$front commitment fee of $18$ percent of the amount of the line.

Based on this information, answer the following:

a$.$ Ignoring the commitment fee, what is the effective annual interest rate on this line of credit? $($Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$

b$.$ Suppose your firm immediately uses $$180$ million of the line and pays it off in one year. What is the effective annual interest rate on this $$180$ million loan? $($Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$