The annual rate of interest is 1.5441% and this can be determined by using the formula of compound interest and the given data.
Given :
The formula of compound interest can be used to determine the annual rate of interest. The formula of compound interest is given by;
[tex]\rm A = P(1+\dfrac{r}{n})^{nt}[/tex]
where A is the final amount, r is the interest rate, n is the number of times interest applied per time period, t is the number of time periods elapsed and P is the principal amount.
Now, substitute the known terms in the above formula.
[tex]56700=56000(1+\dfrac{r}{12})^{12\times 1.6}[/tex]
Simplify the above expression.
[tex]1.025=(1+\dfrac{r}{12})^{19.2}[/tex]
Take the log on both sides in the above expression.
[tex]\rm log(1.025)=19.2\;log(1+\dfrac{r}{12})[/tex]
[tex]\rm \dfrac{log(1.025)}{19.2}=\;log(1+\dfrac{r}{12})[/tex]
Further, simplify the above expression.
[tex]\rm 0.0005585=log(1+\dfrac{r}{12})[/tex]
[tex]\rm 1.001286 = 1+\dfrac{r}{12}[/tex]
[tex]\rm 0.001286 = \dfrac{r}{12}[/tex]
0.015432 = r
To convert the value of 'r' in percentage multiply by 100.
r = 1.5441%
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