A firm offers terms of $\frac{2\mathrm{.}6}{7},$ net $30.$

a$.$ What effective annual interest rate does the firm earn when a customer does not take

the discount? $($Use $365$ days a year. Do not round intermediate calculations and

enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$

b$.$ What effective annual interest rate does the firm earn if the terms are changed to

$3\mathrm{.}6/7,$ net $30,$ and the customer does not take the discount? $($Use $365$ days a year. Do

not round intermediate calculations and enter your answer as a percent rounded to

$2$ decimal places, e$.$g$.,32\mathrm{.}16.)$

c$.$ What effective annual interest rate does the firm earn if the terms are changed to

$2\mathrm{.}6/7,$ net $45,$ and the customer does not take the discount? $($Use $365$ days a year. Do

not round intermediate calculations and enter your answer as a percent rounded to

$2$ decimal places, e$.$g$.,32\mathrm{.}16.)$

d$.$ What effective annual interest rate does the firm earn if the terms are changed to

$2\mathrm{.}6/12,$ net $30,$ and the customer does not take the discount? $($Use $365$ days a year.

Do not round intermediate calculations and enter your answer as a percent

rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$