Homework for Fall 2026 MATH-1100-R02

  1. Thursday, August 26, 2026. Read the syllabus if you have not already done so, and my notes about interest. Visit the course’s site on your Blackboard. Please let me know if I need to correct the list of “See the textbook online” instructions in the class home page. Read pp. 126–129 (up to and including example 3) in the textbook. Get a calculator.

    If you don’t like your photo, you can email me a better one at mmeretzky@fordham.edu, .png format preferred. But it must be 199 × 267 pixels, just like all the others.

  2. Monday, August 31, 2026. I corrected my mistake in p. 16 of Interest. Please make sure you understand everything in this file. Enjoy the semiannually compounded interest song in Mary Poppins.

    Walt Disney’s Donald Duck explains octaves and intervals in this link. Start watching at 2:45. (You’re probably more familiar with Warner Brother’s Daffy Duck, who sounds like he’s from New York.) “Egghead” was a contemptuous term for “intellectual” during the Cold War era (think Adlai Stevenson).

    I believe I made Online Homework #1 visible in Blackboard, due Thursday, September 3, 2026. To see the online homework, follow the See the Online Homework directions on the class home page. Good luck with the seven questions about simple interest.

    You can see the seven questions in Blackboard only if you have paid the $100 extortion. So here they are if you haven’t paid. (Don’t tell anyone I posted this valuable intellectual property on the web.) An answer that is an amount of money should be rounded to two decimal places. That’s because we have 100 cents per dollar.

    1. Find the interest on the following loan.
      $1050 at a 5.5% annual rate for 9 months.
    2. How much interest will you have to pay for a credit card balance of $621 that is 1 month overdue, if a 24% annual rate is charged?
    3. A loan of $20,696 was repaid at the end of 14 months. What size repayment check (principal and interest) was written, if a 6% annual rate of interest was charged?
    4. A loan of $1,080 was repaid at the end of 18 months with a check for $1,095. What annual rate of interest was charged?
    5. A radio commercial for a loan company states: “You only pay 30 cents a day for each $500 borrowed.” If you borrow $2,082 for 256 days, what amount will you repay, and what annual interest rate is the company actually charging? (Assume a 360-day year.)
    6. What annual interest rate is earned by a 14-week Treasury-bill with a maturity value of $1,300 that sells for $1,281.56?
    7. Many tax preparation firms offer their clients a refund anticipation loan (RAL). For a fee, the firm will give a client his refund when the return is filed. The loan is repaid when the Internal Revenue Service sends the refund directly to the firm. Thus, the RAL fee is equivalent to the interest charge for a loan. The schedule in the table on the right is from a major RAL lender. Use this schedule to find the annual rate of interest for a $4,762 RAL, which is paid back in 40 days.
      RAL Amount RAL Fee
      $0 – $500 $29.00
      $501 – $1,000 $39.00
      $1,000 – $1,500 $49.00
      $1,501 – $2,000 $69.00
      $2,001 – $5,000 $89.00
      (Assume a 360-day year.)
  3. Thursday, September 3, 2026. No class on Monday, September 7, 2026; enjoy your long weekend.

    I corrected my mistakes on p. 2 of Future Value of an Annuity. (The mistake was that I should have had five digits: 11111 instead of 1111, and 99999 instead of 9999.) I hope that now you can see some glimmer of beauty in the two contrasting ways of getting to 11111 on that page. “By diverse means we arrive at the same end.” Admire the cleverness of the trick (a multiplication Sx and a subtraction Sx − x) that got us the result on p. 2 with a “wide blank area” in place of a lot of terms. Compare this with the textbook description on p. 149.

    One of the students in the class, scv5@fordham.edu (you can see his picture in Students) has paid his $100 and can see the textbook online, but he cannot see the online homework. If you can see the online homework, please email him and tell him how you did it. I’m afraid I still don’t know how this Pearson thing is supposed to work, but I recognize highway robbery when I see it. Could you help him out?

    Read Section 3.3 (pp. 148–154).

    Written homework. In class on Thursday, September 10, 2026, please hand in the answers to the following three questions on paper, showing your work. Make it legible enough to understand.

    1. [This is just a compound interest question, not an annuity question.] We invest $100 for 10 years. What would give us more money in the end: 6% annual interest, compounded annually; or 5% annual interest, compounded semiannually?
    2. We have an annuity that runs for a total of 10 years. At the end of each year, we deposit $100 into the annuity. What would give us a greater future value (p. 148): 6% annual interest, compounded annually; or 5% annual interest, compounded semiannually?
    3. After brooding for hours about the wisdom of your intended major in Political Science, you fall into a nightmare in which you are reincarnated as John Lindsay, mayor of New York City during the tumultuous years 1966–1973. Every one of your municipal unions has simultaneously gone on strike at midnight, and the entire borough of Queens has just been buried under 100 inches of snow. A startup company in Yonkers that no one has ever heard of claims to have an increasingly potent product named “Greasorb” that, when sprayed from a fleet of helicopters hovering over Flushing Meadows Park, will melt
      1 inch of snow on the first day,
      x additional inches of snow on the second day,
      x2 additional inches of snow on the third day,
      x3 additional inches of snow on the fourth day,
      x4 additional inches of snow on the fifth day,
      etc.
      How big would x have to be in order to uncover the buried denizens of the stricken borough before their air supply runs out at the end of the seventh day? In other words, what is the minimum value of x that would save all these people? Recall that we have a formula giving us the sum of
      x0 + x1 + x2 + x3 + x4 + x5 + x6
      By trial and error, plug different values of x into that formula, to find the smallest value of x (rounded to the nearest hundreth) that would give us a sum of at least 100. (You don’t have to hand in all your unsuccessful trials.)
  4. Thursday, September 10, 2026.
  5. Monday, September 14, 2026.
  6. Thursday, September 17, 2026.
  7. Monday, September 21, 2026.
  8. Thursday, September 24, 2026.
  9. Monday, September 28, 2026.
  10. Thursday, October 1, 2026.
  11. Monday, October 5, 2026.
  12. Thursday, October 8, 2026.
  13. TUESDAY, October 13, 2026.
  14. Thursday, October 15, 2026.
  15. Monday, October 19, 2026.
  16. Thursday, October 22, 2026.
  17. Monday, October 26, 2026.
  18. Thursday, October 29, 2026.
  19. Monday, November 2, 2026.
  20. Thursday, November 5, 2026.
  21. Monday, November 9, 2026.
  22. Thursday, November 12, 2026.
  23. Monday, November 16, 2026.
  24. Thursday, November 19, 2026.
  25. Monday, November 23, 2026.
  26. Monday, November 30, 2026.
  27. Thursday, December 3, 2026.
  28. Monday, December 7, 2026.