While painting your neighbors’ home, the painters spilled a bucket of paint on some important papers, including the amortization schedule for their home mortgage. Since your neighbors know that you are in their neighbourhood, they gave you the only two rows of the amortization schedule that were legible:

99 $2,218.39 $658.33 $1,560.06 $261,773.66

100 $2,218.39 $662.22 $1,556.17 $263,333.72

Required: Assuming that the mortgage’s payments were monthly (in arrears), help them determine:

a. The amount of interest paid in month 100;

b. The mortgage’s APR;

c. The initial amount of the mortgage; and

d. The original length of the mortgage