- Look at the following statements related to the derivation of the lump sum formula:
1: Looked at the total for the first couple of compounding periods
2: Found a common process: multiply by (1 + rate)
3: Took a solution that originally had too many terms and reduced it
to something manageable
4: Used short-term information (local) to derive a global formula
5: Performed mathematical magic - no way to know how we obtained our
formula
In the derivation of the lump sum formula, we
a)all of the above
b)all but 5
c)other
- If a c.d. will
compounded monthly at 3% for 14 years, and William put in $2000,
how much would the c.d. be worth at the end of 14 years?
(a) 2000(1+.03)14
(b) 2000(1+.03/14)14*12
(c) 2000(1+.03/12)14*12
(d) 2000(1+.03/12)14
(e) none of the above
- If a c.d. will
compound annually at 3% for 14 months, and William put in $2000,
how much would the c.d. be worth at the end of 14 months?
(a) 2000(1+.03)14
(b) 2000(1+.03/14)14
(c) 2000(1+.03/12)14*12
(d) 2000(1+.03)14/12
(e) none of the above
- Which of the following are true?
a) The word interest comes from a similar phrase for "that which is
between"
b) Charging interest has been around since at least Babylonian times.
c) Interest rates were once 220%
d) Both b) and c)
e) All of a), b) and c)
- In the case of Benjamin Franklin's fund
a) The earned rate of a fund is the same as the lent
rate that is charged to
borrow the money in the fund.
b) To find the earned rate of a fund, we can calculate a weighted
average rate using the rates each part of the fund actually receives (or
loses).
c) To find the earned rate of a fund, we can use the beginning and ending
values of the fund and calculate the rate in Excel using the lump sum formula.
d) Both a) and c)
e) Both b) and c)
The 5% lent rate marks the expected returns if all the money is lent out
and paid back. It stayed constant. The
average earned rate fluctuates and captures the rate the
fund actually receives in a given timeframe--
the cities couldn't find enough borrowers and some that borrowed didn't pay
what they owed, so the average earned rate was lower.
- Was the lump sum formula approprate to use in the case of the Benjamin
Franklin fund, when money was going in and out of the account?
a) No - Whoops,
we should have used a different formula as it is not a lump
sum.
b) Yes - there is no principal money added in during each 100 year
period - only the lump principal that Benjamin Franklin designated. The
money coming in is only as the loan (a part of the lump sum) and
it's interest.
When we
derived the lump sum formula in class, we added the annual earned interest
to the
amount that was in the account at the beginning of the year to solve for
the savings at the end of the end of the year. We repeated this process
with each successive year
and found a general lump sum formula. By looking at the derivation of
the formula,
it is clear that earned interest is already accounted for within the lump
sum formula, so this is the appropriate formula to use in this case.
c) Yes - We had to use 2 lump sum formulas -
one for the first hundred years and one for the second hundred years -
because Franklin's plan designated that the fund pay out part of it's money
to the cities and states at the end of the first hundred years, so a new
lump sum principal amount needed to be used at the
start of the second hundred years
d) Both b) and c)
e) None of the above
An investment in knowledge pays the best interest [Benjamin Franklin]
- If we put in $100 now and leave it there for 25 years compounded monthly
at 5% how much interest ($) will we have earned?
a) $110.95
b) $248.12
c) $348.12
d) $29550.97
e) none of the above