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

2 & 7

step-by-step explanation:

he climbs 300 ft/hr at a constant rate. the peak is at 1,500 ft.

when going up, he reaches 600 ft in 2 hours. remember, that he is going in a constant rate. divide 600 with 300:

600/300 = 2

assuming that he takes the same route back (meaning that it's a 1500 ft route back, you can solve.

note also that you are solving when he gets back to 600 ft after he reaches the peak.

first, find the amount of hours it takes to get up the peak. divide the total amount (1500), with the ft/her (300) to get the amount of hours (x):

1500/300 = x

x = 5

it takes jamie 5 hours to get up. now, he is returning down, and reaches 600 (his current destination). remember that he climbs at a constant 300 ft/hr. divide 600 with 300:

600/300 = x

x = 2

now add the two numbers together.

x = 5 + 2 = 7

jamie takes 7 hours to go up the mountain and reach his current position when descending.

(total amount/constant rate) = (time).

remember that it is a constant rate, so in total, when he gets back down the mountain, it will take the same amount of time as when he goes up. the total amount for the round trip is: 5 + 5 = 10.

~

i think the amount would be $140.62