The hourly rate is $3 a hour with a $2 initial fee.
<span>A
−10 + 16 = 6
........................................................</span>
6x^2 + 4(x^2 - 1) =
6x^2 + 4x^2 - 4 =
10x^2 - 4 <===
Rate of interest is 6 %
<em><u>Solution:</u></em>
Given in question that,
simple interest = $ 3240
number of years = 9 years
principal sum = $ 6000
To find: interest rate
<em><u>The simple interest is given as:</u></em>

Where, "p" is the principal
"r" is the rate of interest
"n" is the number of years
<em><u>Substituting the values in above formula,</u></em>

Thus rate of interest is 6 %