(-2)^4 = (-2) (-2) (-2) (-2) = 16
so n = 16
$390 is the interest will Charlie’s initial investment earn over the 15-year period. The money does Charlie have after the 15 years is $715.
<u>Step-by-step explanation:</u>
Harlie invests $325 in an account.
- Principal, P = $325
- Interest rate, r = 8% ⇒ 0.08
- Number of years, t = 15
<u>The formula to find the interest will Charlie’s initial investment earn over the 15-year period :</u>
⇒
<u></u>
⇒ 
⇒ 
Therefore, $390 is the interest will Charlie’s initial investment earn over the 15-year period.
<u>Money Charlie has after 15 years :</u>
It is given by the formula,
⇒ Amount = Principal + Interest.
⇒ 325 + 390
⇒ 715 dollars.
∴ The money does Charlie have after the 15 years is $715.