Calculation of period of the loan:
It is given that The loan amount is $6,071 and the annual interest rate is 8%, that means the interest for one year shall be $6,071*8% = $485.68.
Now we are given that the total interest paid is $1,700. The time period of the loan can be calculated by dividing the total interest by the annual interest amount. Hence the period of the loan shall be = 1700 / 485.68 = 3.5 Years.
Hence he had the loan for 3.5 years.