The Mathematics of Money

(Darren Dugan) #1

Copyright © 2008, The McGraw-Hill Companies, Inc.



  1. Carl loaned Jerry $500 on February 12, 2008, and Jerry repaid a total of $515.93 on July 15, 2008. Find the simple
    interest rate for this loan.

  2. Find the maturity value of this promissory note:


Promissory Note
Today, July 30, 2007, I, Erwin Addison, acknowledge a loan of
$25,000 made to me by the Fourth National Bank of Portville,
and agree to repay this loan on September 19, 2007, together
with simple interest calculated at a rate of 9% per annum.


  1. According to doomsayers, the ancient Mayan calendar terminates on December 21, 2012, and therefore the world will
    end on that date. How many more days do we have left?

  2. Andriy deposited $4,500 in a 1-year CD paying 6.15% simple interest. How much interest will he earn?

  3. Calculate the simple interest on an $80,000 loan for 210 days at a simple interest rate of 12.285%. Assume that
    bankers’ rule is being used.

  4. A small business owner borrowed $19,275.13 and paid $21,045.61 to settle the debt. How much total interest did she pay?

  5. The Tilsonboro Savings Bank pays 5.38% simple interest on 6-month certifi cates of deposit. If you deposit $12,500 in
    such a CD, how much will it be worth when it matures?

  6. A roofi ng contractor took out a short-term loan for $15,000 to pay for materials. The simple interest rate was 8% per
    annum, and the term was 21 days. Find the total interest paid.

  7. Your mobile phone statement shows a balance of $178.59 and the payment is due on April 20. The statement says that
    payments received more than 15 days late will be charged a $20 late payment fee. By what date must you pay your
    balance to avoid the fee?

  8. Ralyd Pharmaceuticals’ patent on its top-selling drug expires on May 15, 2009. How many days of this patent were left
    on November 8, 2006?

  9. Determine the total amount required to repay a $5,000, 3-year loan if the simple interest rate is 10.3% per annum.

  10. Find the total interest for a 15-month loan of $98,359.25 if the simple interest rate is 5.05%.


Chapter 1 Exercises 53
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