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 $\frac{3\mathrm{.}6}{7},$ 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 $2\mathrm{.}67,$ 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 $\frac{2\mathrm{.}6}{12},$ 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$.,32\mathrm{.}16.)$

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