Interest

• Calculating Interest on Auto Loans [Sampath, 7/10/1996]
  How do the the lien holders for auto loans calculate interest on the principle?

• Coal Consumption [Plascencia, 01/13/1997]
  How long will coal reserves last if consumption increase at the rate of 3.1 percent per year?

• Formula for Compound Interest [Knorppn, 3/31/1995]
  Please send the formula(s) for calculating interest compounded annually, daily, and continuously.

• Interest: Definitions [Taylor, 9/25/1996]
  What is compound interest? What is continuous compounding?

• Paying off the Mortgage [Holder, 10/08/1998]
  You have a 30-year mortgage with monthly payments of $370 at 8%. If you instead pay $400 each month, when will you pay it off?

• Rate vs. Yield [Jill, 01/31/2002]
  What is the interest amount for the period from Sept. 05, 2001 to Dec. 04, 2001, at 5% interest, compounded daily, on principal of $356,964.15?

• Compound Interest - Rule of 70 [Nishisaka, 11/29/1994]
  There is a famous "Rule of 70" for compound interest. What is it and why does it work?

• Amount of Interest Earned in a Year [Bunjef, 11/28/1995]
  If Li Fong had earned one fourth of a percent more in annual interest on an investment, the interest for one year would have been $45 greater. How much did she invest at the beginning of the year?

• An Annuity [Tanne, 12/13/1995]
  Compound interest with monthly installments.

• Credit Card Calculations [Jarmie, 1/24/1996]
  I have textbooks and programs, none of which cover the calculation typical of credit card balance payoffs - how long will it take?

• Interest Rates [Turnham, 4/4/1996]
  At what rate of simple interest would the amount to be repaid on a loan be triple the principal of the loan after 25 years?

• Investments [Mbfal, 5/30/1996]
  Nancy has inherited $80,000... her annual return on three investments is $6800. How much is invested in each?

• Formula for 8 Percent Interest [Kelly, 5/31/1996]
  I put $15 a month into a saving account and at the end of each year I get 8 percent interest...

• Exponential Growth & Compound Interest [Kay, 6/2/1996]
  (1) The cost of goods and services in an urban area increased 1.5% last month. If the rate continues, what will be the annual rate of increase? (2) Suppose a certain population increases by 30% every 10 years. By what percent does it increase each year?

• Quarterly Interest [Dickenson, 6/3/1996]
  How long will it take for a sum deposited in a savings account to double at 6 percent interest compounded quarterly?

• Formula for Mortgage [Patrick, 7/4/1996]
  What is the formula for a mortgage?

• Setting Interest Rate to Maximize Profit [Lisa, 7/25/1996]
  A loan company is limited to charging maximum 18 percent interest on a loan. The amount of money available for loans is proportional to the interest rate the company will pay its investors...

• Income from Winning the Lottery [Medlin, 7/30/1996]
  How much money would I need to win in the lottery to have an income of $75,000.00 year until I die? That should be in about 30 more years.

• Solving for Rate [Bradie, 8/8/1996]
  In the equation P=V*R/(1-(1+R)^(-n)), how do you solve for "R"?

• 15 Percent Annual Interest [Eastman, 8/24/1996]
  How much money will I will have in 29 years if I save $120 per month at 15 percent annual interest?

• Setting up Interest Problems [Osborn, 9/7/1996]
  If I have $10K in principle, and invest part in a 12 percent interest fund, and the rest in a 15 percent interest fund, and the income after a year is $1,275, how much was invested in each fund?

• Salary at 5 Percent Yearly Increase [Pawlosky, 9/11/1996]
  Martin starts work at $18,000/year and receives an annual increase of 5 percent. What is his salary after 30 years?

• Loan Amortization [Stafford, 9/12/1996]
  What is the formula for loan amortization?

• Monthly Compounded Interest [Beeman, 10/24/1996]
  Please give me the formula for monthly compound interest accruing annually.

• Proof that INT(1/x)dx = lnx [Faulkner, 11/08/1996]
  How do you integrate (1/x)dx?

• Loan Terms and APR [Schlee, 02/18/1997]
  Formula for annual percentage rate.

• The Nature of e [Chen, 02/23/1997]
  Why is e considered natural?

• Semi-annual Compounding [Bacchus, 04/03/1997]
  Given a 6 percent annual yield, find the rate of interest when compounded semiannually.

• Compound Interest [Charles, 04/11/1997]
  How many years will be needed for $5000 to increase to $22,000 at 11 percent interest compounded monthly?

• Endowment Awards [Donna, 05/09/1997]
  An endowment of $15,000 is made which earns 7.25% interest compounded continously. How large must the endowment grow for it to support an annual award of $1,200 in perpetuity?

• Credit Card Debt [Frost, 05/09/1997]
  How do credit card companies figure out how long it will take to pay off debt?

• Compound interest to a specific amount [Burke, 07/24/1997]
  How long would it take for a regular deposit account to equal one million dollars, assuming monthly payments of $100.00 at 8, 10 and 12 percent interest?

• Compound interest with Repayments [Worthington, 07/24/1997]
  I need a compound interest formula with repayments, such as in a bank situation.

• Compound Interest [Echols, 07/30/1997]
  I want to buy a car that costs $20,058.00 and would like to know how they calculate the interest on my loan.

• Monthly Saving [Neath, 08/13/1997]
  What is the regular monthly saving required to accumulate a known balance at a point in the future?

• Car Loan Rates [Fulton, 08/27/1997]
  Can you help me calculate the impact of different interest rates on a 5-yr. car loan (60 payments) of $20,000?

• Recursive Function for Loan Problem [Hotetz, 11/13/1997]
  What is the recursive function formula for a loan of $100,000, payable at 6 percent, over 20 years?

• Paying Off a Loan [Grant, 11/14/1997]
  You want to borrow $25,000 at 6.9% to buy a new car...

• Euler's Number [Holcomb, 01/28/1998]
  Why is Euler's number referred to as the natural base?

• History and Applications of the Natural Logarithm [Fornwalt, 03/02/1998]
  I'm so surprised at how often the number e comes up. Where did it come from? Who first derived it? Why is it so common in the field of biology?

• Extra Loan Payments, Amortization Tables [Haynes, 03/31/1998]
  If one extra payment is made each year, how much money will be saved over the life of a 30-year mortgage and how much sooner will it be paid off?

• Analyzing Monthly Payments [Holmes, 05/13/1998]
  How much principal and how much interest have been paid after n payment cycles?

• Rule of 72 [Hodge, 08/06/1998]
  How do you use the rule of 72?

• Return on Investments [Quinn, 10/14/1998]
  What is the formula for calculating the return on investments (ROI) in a percentage?

• Compounding Interest and e [Radway, 11/11/1998]
  How is the number e derived from compounding interest? Does it come from the series expansion of e?

• Rule of 72 [Vasseur, 01/26/1999]
  Why does the rule of 72 work? For what interest values does it work best?

• Declining Balance Interest [Maria, 03/22/1999]
  Can you explain declining balance interest to a high school business class?

• Savings, Superannuation, and Investments [Yang, 04/18/1999]
  You invest $400 per month at 8 percent per annum calculated monthly. Calculate the amount accumulated...

• Dividing Investments for Maximum Return [Andrew, 09/26/1999]
  How should one invest $60,000 in mutual funds with a return of 10% and municipal bonds with a return of 12% in order to maximize income?

• Rule 78 Amortization with Balloon Payment [Alvarez, 09/29/1999]
  An amortization schedule, using the RULE-78 method, for a loan with a balloon payment.

• Half Life of Money [Davis, 04/13/2001]
  What is the standard accepted formula for determining the amount of time it takes for money to lose half of its value due to inflation? I've found two, they are: t = t = log2/r and t = log2/log(1+r).

• Finding Roots on a Calculator [Moore, 04/22/2001]
  How can I use the equation HPR = (1.667)^(1/5) on a calculator that does not have a fifth root key?

• Retirement Savings [Dan, 05/07/2001]
  How can I calculate how much money I'll need to save each month from age 25 to age 65 at 5% compound interest so that I can withdraw $1,000 each month from age 65 to 80 without running out?

• Compound Interest [Brandon, 05/30/2001]
  Computing compound interest with known variables.

• Long First Month Mortgage Payment Calculation [Genevieve, 06/22/2001]
  In the real world, if one applies for a loan, the first payment generally is not exactly one month from the time the loan is taken...

• Opposite of Percentage [Marty, 07/31/2001]
  I am trying to write a document explaining a common procedure: calculating a discounted price. What is the name given to the term (1- discount_rate)?

• Annuities [Russ, 12/31/2001]
  If I have $100,000 at 5% interest and withdraw from it for 20 years, leaving a zero balance, how much monthly income will I have?

• Doubling Time [Ariele, 03/08/2002]
  If the cost of an all-day ski lift ticket at Colorado's Vail Ski Area has been growing at about 7% per year ever since 1963, when a ticket was $5, what did it cost in 1993?

• Financial Calculator: PerSense [Satadru, 03/19/2002]
  What I understand is that part of the payment I make each month goes toward payment of the interest on the current balance of the loan, and part of it goes toward paying off the principal. Can you explain?

• Time Value of Money [Daniel, 03/20/2002]
  Determine the annual percentage rate of yield or return on an investment.

• Amount of an RRSP [Veronica, 03/24/2002]
  Brian makes $2500 deposits into his Registered Retirement Savings Plan on his 20th, 25th, 30th, 35th, and 40th birthdays. The RRSP pays 7% per annum, compounded annually. Determine the value of Brian's RRSP when he's 65.