Award: $5\mathrm{.}00$ points

A firm offers terms of $\frac{2}{20},$ net $50.$

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

Note: 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 discount is changed to $3$ percent?

Note: 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 credit period is increased to $70$ days?

Note: 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 discount period is increased to $25$ days?

Note: Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$

$\backslash$table$[[$a$.$ Effective annual interest rate,$],[$b$.$ Effective annual interest rate,$\%$