A college graduate just got a job in Indianapolis. She is considering

buying a house with a $$200,000$ mortgage. The APR is $4\%$ compounded

monthly for her monthly mortgage payments on a $30-$year fixed rate loan.

If she can get her FICO score up to $750,$ the APR drops to $3\mathrm{.}6\%.$ How much

in interest cost will she save over the life of the loan assuming she can

increase her FICO score to $750?$