Cameron is saving for his retirement $20$ years from now by setting up a savings plan. He has set up a savings plan wherein he will deposit $$141\mathrm{.}00$ at the end of every six months for the next $11$ years. Interest is $11\%$ compounded semi$-$annually.

$($a$)$ How much money will be in his account on the date of his retirement?

$($b$)$ How much will Cameron contribute?

$($c$)$ How much will be interest?