(c) Rs 100000
Let the principal sum be Rs x. Then,
Amount (at interest compounded annually)
= x\(\big(1+\frac{20}{100}\big)^2\) = \(\frac{36X}{25}\)
Amount (at interest compounded half yearly)
= x\(\big(1+\frac{10}{100}\big)^4\) = \(\frac{14641X}{10000}\)
Given, \(\frac{14641X}{10000}\)- \(\frac{36X}{25}\) = 2410
\(\Rightarrow\) \(\frac{14641X-14400X}{10000}\) = 2410
\(\Rightarrow\) \(\frac{241X}{10000}\) = 2410 \(\Rightarrow\)x= Rs 100000