A firm offers terms of $1/10,$ net $60.$

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 $2/10,$ net $60,$ 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 $1/10,$ net $75,$ 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 $1/15,$ net $60,$ 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$.,32\mathrm{.}16.)$