Answer:
$3,874.57
Step-by-step explanation:
To calculate how much money Buffy will make in total over 7 weeks, we can use the formula for the sum of the first n terms of a geometric series
[tex]\boxed{\begin{minipage}{7 cm}\underline{Sum of the first $n$ terms of a geometric series}\\\\$S_n=\dfrac{a(1-r^n)}{1-r}$\\\\where:\\\phantom{ww}$\bullet$ $a$ is the first term. \\ \phantom{ww}$\bullet$ $r$ is the common ratio.\\\end{minipage}}[/tex]
In his first week of business, Buffy's profits were $282.
Therefore, a = 282.
As his profits increase by 22% each week, his revenue is 122% of the previous week. As a decimal, 122% = 1.22.
Therefore, r = 1.22.
We want to find the total amount he will make over 7 weeks.
Therefore, n = 7.
Substitute the values of a, r and n into the formula and solve:
[tex]\begin{aligned}S_7&=\dfrac{282(1-1.22^7)}{1-1.22}\\\\&=\dfrac{282(1-4.0227108...)}{-0.22}\\\\&=\dfrac{282(-3.0227108...)}{-0.22}\\\\&=\dfrac{-0.852.404454...}{-0.22}\\\\&=3874.5657\end{aligned}[/tex]
Therefore, the total amount Buffy will make over 7 weeks is $3,874.57 to the nearest cent.