If the compound interest on a certain sum for three years at 10% is Rs

1.	If the compound interest on a certain sum for three years at 10% is Rs 993, what would be the simple interest on the same sum at the same rate for the same time ? (a) Rs 930 (b) Rs 920 (c) Rs 900 (d) Rs 890
Answer» (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.

If the compound interest on a certain sum for three years at 10% is Rs 993, what would be the simple interest on the same sum at the same rate for the same time ? (a) Rs 930 (b) Rs 920 (c) Rs 900 (d) Rs 890

Answer»

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.