Respuesta :

Answer:

The rate of interest is 9.5092%  

Step-by-step explanation:

Given as :

The investment amount = p = $857

The Amount after 6 years = A = $1268.36

The time period = t = 6 years

Let The rate of interest = r%

Now, From Compound Interest method

Amount = Principle × [tex](1+\dfrac{\textrm rate}{100})^{\textrm time}[/tex]

Or, A = p × [tex](1+\dfrac{\textrm r}{100})^{\textrm t}[/tex]

Or, $1268.36 = $857 × [tex](1+\dfrac{\textrm r}{100})^{\textrm 6}[/tex]

Or, [tex]\dfrac{1268.36}{857}[/tex] =  [tex](1+\dfrac{\textrm r}{100})^{\textrm 6}[/tex]

Or, 1.48 =  [tex](1+\dfrac{\textrm r}{100})^{\textrm 6}[/tex]

Taking power [tex]\dfrac{1}{6}[/tex]  both side

So, [tex]1.48^{\frac{1}{6}}[/tex] = [tex]((1+\dfrac{r}{100})^{6})^{\frac{1}{6}}[/tex]

Or, 10.5092 = 1 + [tex]\dfrac{r}{100}[/tex]

Or, 10.5092 - 1 = [tex]\dfrac{r}{100}[/tex]

Or, 9.5092 = [tex]\dfrac{r}{100}[/tex]

∴   r % = 9.5092

So , The rate of interest = r = 9.5092 %

Hence, The rate of interest is 9.5092%   Answer