To pay for a $$19,800$ fishing boat, Jane made a down payment of $$4800$ and took out a loan for the rest. On the loan, she paid monthly payments of $$269\mathrm{.}54$ for $5$ years.

$($a$)$ What was the total amount Jane ended up paying for the fishing boat $($including the down payment and monthly payments$)?$

$ II

$($b$)$ How much interest did Jane pay on the loan?

$$$