Answer:
Benedict will take less time pay off his loan as compared to his brother Francis. If Francis pay off $100 per year then it will take almost 20 years to pay him off the loan and approx two years for the interest which will be accumulating 6% annually and will become almost $120 in 20 years, whereas, Benedict, starting from 4 years from now by paying $150 per year will take
1Year 2Year 3 Year 4Year 5Year 6Year 7Year 8Year 9Year
$0 $0 $0 $0 $150 $150 $150 $150 $150
10Year 11Year 12Year 13Year 14Year 15Year 16year 17Year 18Year
$150 $150 $150 $150 $150 $150 $150 $150 $150 = $2000
Therefore, Benedict will take less time to pay off his loans.