Given, P = 10 crore and population after 3 yr = 13.31 crore

According to the formula,

Population after n yr = \( \Large P \left(1+ \frac{R}{100}\right)^{n} \)

=> 13.31=\( \Large 10 \left(1+ \frac{R}{100}\right)^{3} \)

=> \( \Large \frac{1331}{1000} \)= \( \Large \left(1+ \frac{R}{100}\right)^{3} \)

=> \( \Large \left(\frac{11}{10}\right)^{3} \)=\( \Large \left(1+ \frac{R}{100}\right)^{3} \)

=> \( \Large 1+ \frac{R}{100} \)=\( \Large \frac{11}{10} \)

=> \( \Large \frac{R}{100}=\frac{11}{10}-1=\frac{1}{10} \)

R=10%