Mrs. Shaw takes out a $180 000 mortgage on a new house. The interest rate is 6.4%/a, compounded semi-annually.

If she makes monthly payments of $1200.00, how long will it take to pay off the mortgage? How much interest is paid over the life of the mortgage?

How much interest would Mrs. Shaw save over the life of the mortgage if she made accelerated bi-weekly payments of $600.00?

( the last one underlined, i need that answer) and i need it asap please thanks