Compound Interest Ques 1
Question
Rs. 6100 was partly invested in Scheme A at $10 \%$ p.a. compound interest (compounded annually) for 2 years and partly in Scheme B at $10 \%$ p.a. simple interest for 4 years. Both the schemes give equal interests. How much was invested in Scheme A ?
(1) Rs. 3,750
(2) Rs. 4,500
(3) Rs. 4,000
(4) Rs. 3,250
(5) Rs. 5,000
(IBPS Bank PO/MT CWE-V (Preliminary) 03.10.2015)
Show Answer
Answer: (3)
Solution: (3)
Amount invested in scheme $A=Rs . x$ (let)
$\therefore$ Amount invested in scheme $B=$ Rs. $(6100-x)$
According to the question,
$ P_{1}\left[\left(1+\frac{R_{1}}{100}\right)^{T_{1}}-1\right]=\frac{P_{2} R_{2} T_{2}}{100} $
$ \begin{aligned} & \Rightarrow x\left[\left(1+\frac{10}{100}\right)^{2}-1\right] =\frac{(6100-x) \times 10 \times 4}{100} \\ & \Rightarrow x\left[\left(\frac{11}{10}\right)^{2}-1\right]=\frac{4(6100-x)}{10} \\ & \Rightarrow x\left(\frac{121-100}{100}\right)=\frac{4(6100-x)}{10} \end{aligned} $
$\Rightarrow \frac{21 x}{100}=\frac{24400-4 x}{10}$
$\Rightarrow 21 x=244000-40 x$
$\Rightarrow 21 x+40 x=244000$
$\Rightarrow 61 x=244000$
$\Rightarrow x=\frac{244000}{61}=$ Rs. 4000