Ireally need ! i cant figure these out.

what is the future value of the 10% savings from earnings of $1,470 if it earns 3.5% annual interest,

compounded monthly for 25 years?

use the compound interest formula to estimate the future value.

a = p (1+r/n)^nt

a.

$295.72

b.

$352.19

c.

$419.43

d.

$523.89

what is the future value of the 10% savings from earnings of $36,000 if it earns 6.25% annual interest, compounded quarterly for 15 years?

use the compound interest formula to estimate the future value.

a = p (1+r/n)^nt

a.

$912.65

b.

$9,126.53

c.

$1,825.31

d.

$18,253.31

justin contributes $208 each month to a savings account that earns 5% annual interest. calculate his annuity savings over the course of 25 years.

use

s = p ((1+r^n)-1/r)

a.

$9.927.23

b.

$65,520.00

c.

$62,660.00

d.

$123,866.02

Step-by-step explanation:

First of all, the formulas need to be written correctly, and you need to understand what the variables mean. Usually, the variables have these meanings:

Usually, an annual interest rate is quoted and compounding is annual (n=1), quarterly (n=4) or monthly (n=12). In some formulas, r is the monthly rate and n is the number of months (there is no "t" in such formulas).

When we say "written correctly", we mean that parentheses are needed around exponents and denominators. In the formulas you have here, necessary parentheses are missing or misplaced, so you cannot use these formulas directly in your calculator or spreadsheet. If you're copying formulas from a question where they're typeset, be aware of the grouping effect of fraction bars and superscripts and use parentheses accordingly.

In the first two problems, you're not given P directly. Rather, the principal invested is to be computed as 10% of the amount given as "earnings."

___

1. P = $147; r = 0.035; n = 12; t = 25.

  A = P(1 + r/n)^(nt) = 147·(1 + .035/12)^(12·25) ≈ 147·1.002916667^300

  A ≈ 352.19 . . . . matches choice B

___

2. P = $3600; r = 0.0625; n = 4; t = 15.

  A = P(1 + r/n)^(nt) = 3600·(1 + .0625/4)^(4·15) ≈ 3600·1.01625^60

  A ≈ 9126.53 . . . . matches choice B

___

3. P = $208; r = 0.05/12; n = 300. Here, r is the monthly rate, n is the number of months. Please note the correction of the formula. The variable "S" refers to the Sum of payments and interest. This is effectively the sum of a geometric sequence, so the formula should look familiar on that basis.

  S = P((1 +r)^n -1)/r = 208·((1.004166667^300 -1)/0.004166667

  S ≈ 123,866.02 . . . . matches choice D

step-by-step explanation: