Rate of interest is 6 %
Solution:
Given in question that,
simple interest = $ 3240
number of years = 9 years
principal sum = $ 6000
To find: interest rate
The simple interest is given as:
[tex]S.I = \frac{pnr}{100}[/tex]
Where, "p" is the principal
"r" is the rate of interest
"n" is the number of years
Substituting the values in above formula,
[tex]3240 = \frac{6000 \times 9 \times r}{100}\\\\3240 = 60 \times 9 \times r\\\\3240 = 540 \times r\\\\r = \frac{3240}{540}\\\\r = 6[/tex]
Thus rate of interest is 6 %