Mr$.$ Smith is purchasing a $ $140000$ house. The down payment is $20$

$\%$ of the price of the house.

He is given the choice of two mortgages:

a$)$ a $20-$year mortgage at a rate of $7\%.$

Find

$($i$)$ the monthly payment: $$$

$($ii$)$ the total amount of interest paid: $$$

b$)$ a $15-$year mortgage at a rate of $7\%.$

Find

$($i$)$ The monthly payment: $$$

$($ii$)$ the total amount of interest paid: $$$