Friendly's Quick Loans, Incorporated, offers you $"$ $$3\mathrm{.}90$ for $$4\mathrm{.}90$ or I knock on your door." This means you get $$3\mathrm{.}90$ today and repay $$4\mathrm{.}90$ when you get your paycheck in one week $($or else$).$

a$.$ If you were brave enough to ask, what APR would Friendly's say you were paying? $($Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$

b$.$ What's the effective annual return Friendly's earns on this lending business? $($Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$