What would be the net annual cost of the following checking accounts?

a$.$ Monthly fee, $$3\mathrm{.}85$; processing fee, $$0\mathrm{.}30$ cents per check; checks written, an average of $20$ a month. Note: Do not round intermediate calculations. Input the answer as a positive value. Round your final answer to $2$ decimal places.

Net annual cost

b$.$ Interest earnings of $7$ percent with a $$500$ minimum balance; average monthly balance, $$600$; monthly service charge of $$15$ for falling below the minimum balance, which occurs three times a year $($no interest earned in these months$).$

Note: Do not round intermediate calculations. Input the answer as a positive value. Round your final answer to $2$ decimal places.

Net annual cost