A loan is repaid with monthly payments that start at 325 at

A loan is repaid with monthly payments that start at $325 at the end of the first month and increase by $15 each month until a payment of $2,215 is made, after which they cease. If the annual effective interest rate is 7%, find the amount of principal in the sixtieth payment. (Round your answer to the nearest cent.)

Solution

Interest (i)=$2215

Effective rate (r)=7%

Number of months (n)=60= 5 years

Principal amount =(p) ?

I=p*r*n/100

2215 = p* 7* 5/ 100

P= 2215*100/7*5

P=6328.5

Principal amount = 6329$