### More Interest Formulas

#### Uniform annual series and future value

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Suppose that there is a
series of "n" uniform payments, uniform in amount and uniformly
spaced, such as a payment every year. Let "A" be the amount of each
uniform payment.

Let "F" be a
future, single amount equivalent to the series, with "F" occurring at
the same time as the last "A" payment. Then the relationship between
F and A is:

F = A [ (1 + i) ^{n}
- 1 ] / i

Example: If $100 is invested
at the end of each year for the next 10 years in a savings account that pays 5%
interest, how much will be in the account immediately after the tenth payment?

F is the unknown.

A = $100 per year

i = 5%, understood to be 5%
per year, compounded annually.

n = 10 years

F = A [ (1 + 0.05) ^{10}
- 1 ] / 0.05

= $100 [ (1.05) ^{10}
- 1 ] / 0.05

= $100 (0.6289 / 0.05) =
$1,258.

Or, using the 5% interest
table, which is quicker:

F = A (F/A,5%,10) = $100 (
12.578 ) = $1,258.

### More Interest Formulas

#### Uniform annual series and future value

Question 1

Question 2

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annual series and future value

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Question 1.

Suppose that
$1,000 is invested quarterly at 6% interest, compounded quarterly. How much
will be in the account after five years?

Choose an answer by clicking on one of the letters below, or click on
"Review topic" if needed.

A F = A (F/A,6%,5) = $1,000 (5.637) = $5,637

B F = A (F/A,1.5%,5) = $1,000 (5.152) = $5,152

C F = A (F/A,1.5%,20) = $1,000 (23.124) = $23,124

D F = A (A/F,1.5%,20) = $1,000 (0.0432) = $43.20

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topic

Question 2.

Suppose an
investor plans to make monthly deposits into an account that pays 9% interest,
compounded monthly, so that $100,000 will be in the account immediately after
the payment at the end of Year 10. The first payment will occur at the end of Month
1 (one month from the present). How much must be deposited monthly?

Choose an answer by clicking on one of the letters below, or click on
"Review topic" if needed.

A A = F (F/A,0.75%,120) = $100,000 (193.517) = $19,351,700 per month

B A = F (A/F,0.75%,120) = $100,000 (0.00517) = $517 per month

C A = F (A/F,9%,10) = $100,000 (0.0658) = $6,580 per month

D A = F (A/F,0.75%,10) = $100,000 (0.0967) = $9,670 per month

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topic