A bank account balance, b, for an account starting with s dollars, earning an annual interest rate, r, and left untouched for n years can be calculated as Find a bank account balance to the nearest dollar, if the account starts with $200, has an annual rate of 4%, and the money left in the account for 10 years.
well, assuming is "simple interest" rate
\(\bf \qquad \textit{Simple Interest Earned Amount}\\\\
A=P(1+rt)\qquad
\begin{cases}
A=\textit{accumulated amount}\\
P=\textit{original amount deposited}\to& \$200\\
r=rate\to 4\%\to \frac{4}{100}\to &0.04\\
t=years\to &10
\end{cases}\)
Answer:
Part A:
As any particular interest is not mentioned, we will calculate the simple interest formula.
\(SI=p\times r\times t\)
Now as per given scenario, here p is s.
t is n
So, we can calculate interest as:
\(I=s\times r\times n\)
And \(b=s+I\)
Part B:
Here p = 200
r = 4% or 0.04
t = 10 years
So, interest is \(200\times0.04\times10=80\) dollars
And amount after 10 years is = \(200+80=280\) dollars