What is the interest during the fifth period (year) if the constant interest rate is 5% and the cash value is 15,000 currency units? The periodic payment is seven years.
現在価値が 15,000 貨幣単位で一定利率が 5% とします。７年間定期的に支払いが行われる場合の第５期 (年) の金利を求めます。