91 vote
The compound interest earned in two years at 15% per annum is Rs 20640. What is the sum invested (in Rs)?
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The compound interest earned in two years at 15% per annum is Rs 20640. What is the sum invested (in Rs)?
1). 64000
2). 60000
3). 56000
4). 52000
3 answers
22 vote
Let the sum invested = Rs. $100x$
Rate of interest $= 15%$ and time period $= 2$ years
Compound interest $= P[(1+\frac{r}{100})^t-1]$
=> $100x[(1+\frac{15}{100})^2-1]=20640$
=> $100x[(\frac{23}{20})^2-1]=20640$
=> $100x(\frac{529-400}{400})=20640$
=> $\frac{129x}{4}=20640$
=> $x=20640 \times \frac{4}{129}$
=> $x=160 \times 4=640$
$\therefore$ Sum invested $= 100 \times 640$=Rs. $64,000$
=> Ans - (A)
32 vote
Let the P is = x
Compound Interest for 2 years $ = 2 \times \frac{15}{100} \times x + \frac{15}{100} \times \frac{15}{100} \times x = 20640 $
On Solving $x = 64000$