You have a choice between a 30-year fixed rate loan at % and an adjustable rate mortgage (ARM) with a first year rate of %. Neglecting compounding and changes in principal, estimate your monthly savings with the ARM during the first year on a $ loan. Suppose that the ARM rate rises to % at the start of the third year. Approximately how much extra will you then be paying over what you would have paid if you had taken the fixed rate loan?