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 %