The amount of the monthly repayments on a loan of $70000$ with $4\%$ interest is given by the formula M$=700000\mathrm{.}04(1\mathrm{.}04)^$n$/(1\mathrm{.}04)^$n$-1$ where n is the number of monthly repayments to be made. $($a$)$ How much is the monthly repayment, if the loan is to be paid in one year $($so n$=12)?[5]($b$)$ If we want the monthly repayments M to be $3000,$ hoy many months will it take to repay the loan in full? $[10]$