You plan to purchase an $$120,000$ house using a $15-$year mortgage obtained from your local bank. The mortgage rate offered to you is $4\mathrm{.}25$ percent. You will make a down payment of $10$ percent of the purchase price.

a$.$ Calculate your monthly payments on this mortgage.

b$.$ Calculate the amount of interest and, separately, principal paid in the $90$th payment.

c$.$ Calculate the amount of interest and, separately, principal paid in the $110$th payment.

d$.$ Calculate the amount of interest paid over the life of this mortgage.

$($For all requirments, do not round intermediate calculations. Round your answer to $2$ decimal places. $($e$.$g$.,32\mathrm{.}16))$