Respuesta :
There are 46 interest payments in 23 years so we divide this number into 2*72 = 144.
Required interest rate = 144 / 46 = 3.13 % answer
Answer:
3.13%
Step-by-step explanation:
We have been given that Arnulfo deposited $55 into a savings account for which interest is compounded semiannually.
The rule of 72 states that to find the number of years needed to double our money at a given interest rate, we just divide 72 by the interest rate (r).
[tex]\text{Number of years it will take to double the money}=\frac{72}{r}[/tex], where r represents the interest rate.
As we have been given that it will take approximately 23 years to double Arnulfo's money, so we can set an equation as:
[tex]23=\frac{72}{r}[/tex]
Let us solve for r .
[tex]r=\frac{72}{23}[/tex]
[tex]r=3.1304347826086957\approx 3.13[/tex]
Therefore, at a interest rate of 3.13% Arnulfo's money will be doubled in approximately 23 years.
