$\text{Given that }\$7000 \text{ is compounded semiannualy at a rate of }11\% \text{ for 21 years}\\
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\text{we know that the amount after t year when compounded is given by}\\
\\
A=P\left ( 1+\frac{r}{n} \right )^{nt}\\
\\
\text{here P is the principal amoount, so }P=7000,\\
\\
\text{r is the interest rate, }r=11\%=0.11\\
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\text{n is the number of times in a year, here semiannulay, so }n=2,\\
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\text{and t is the time, so }t=21\\
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\text{so the amount after 21 years is}$

$A=7000\left ( 1+\frac{0.11}{2} \right )^{2(21)}\\
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\Rightarrow A=7000\left ( 1+0.055 \right )^{42}\\
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\Rightarrow A=7000\left ( 1.055 \right )^{42}\\
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\Rightarrow A\approx 66328.68$

So the amount after 21 years is: $66328.68

7 0

3 years ago

You run 18 miles in 2 hours and 45 miles in 5 hours how fast are you running

Lesechka [4]

So let's find the unit rate of these.

18 mi/ 2 hrs = 9 mi/ 1hr

45 mi / 5 hrs = 9 mi/ 1 hr

So you are running 9 miles an hour.

If you have any questions please comment! :)

6 0

3 years ago

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