(c) Rs 900
Given, 993= P\(\Big[\big(1+\frac{10}{100}\big)^3-1\Big]\)
\(\Rightarrow\) 993 = P\(\Big[\big(\frac{11}{10}\big)^3-1\Big]\) \(\Rightarrow\) 993 = P\(\Big[\frac{1331-1000}{1000}\Big]\)
\(\Rightarrow\) P = \(\frac{993\times1000}{331}\)
\(\Rightarrow\) P = Rs 3000.
\(\therefore\) S.I = Rs\(\frac{3000\times3\times10}{100}\)= Rs 900.