If we were to find the interest on a sum of money for 3 years 4 months 5
days, we would find the interest for 1 year, then for 1 month (1/12 of a
year), then for 1 day (1/360 of a year). Having the interest for 1 year
1 month 1 day, it is a simple matter of multiplication to get it for 3
years 4 months 5 days.