SSC CPO SI and ASI Model Paper 10

(2) Let k be the interest for the firstyear and the rate of interest be r%per annum.
Now
$\mathit{k}\left[1+\frac{\mathit{r}}{100}\right]-\mathit{k}=360$
⇒kr = 360If rate of interest becomes 3 times,then interest for the 1st year = 3k
Difference between the compoundinterest for the second year and thefirst year
$=3\mathit{k}\left[1+3\frac{\mathit{r}}{100}\right]-3\mathit{k}=\frac{9\mathit{k}\mathit{r}}{100}$
Putting the value of $\frac{\mathit{k}\mathit{r}}{100}$we get
$\frac{9\mathit{k}\mathit{r}}{100}=9\times 360=\mathit{₹}3,240$