Respuesta :

Given

investment = $1200  

earned in interest = $ 66

Time =  one year

Find out the interest rate .

To proof

FORMULA

[tex]Simple\ interest =\frac{Principle \times Rate\times Time}{100}[/tex]

here

Principle =$ 1200

Simple interest =$66

Time = 1 year

put these value in the above formula

we get

[tex]Rate =\frac{66 \times100 }{1200}[/tex]

Rate = 5.5 %

The interest rate is 5.5 %

Hence proved