If ₹ $1000$ is invested at an interest rate of $5 \%$ and the interest is added to the principal every $10$ years,then the number of years in which it will amount to ₹ $2000$ is:

$A$ sum of ₹ $25400$ was lent out in two parts,one at $12 \%$ and the other at $12 \frac{1}{2} \%$. If the total annual income is ₹ $3124.2$,the money lent at $12 \%$ is (in ₹):

Heena invests an amount of $10250$ at $4$ $p.c.p.a.$ to obtain a total amount of $Rs. 12710$ on simple interest after a certain period. For how many years did she invest the amount to obtain the total sum?

The rate of interest for the first $2$ years is $3 \%$ per annum,for the next $3$ years is $8 \%$ per annum,and for the period beyond $5$ years is $10 \%$ per annum. If a man gets $Rs. 1520$ as simple interest for $6$ years,how much money (in $Rs.$) did he deposit?

An investor invested his savings in the stock market. The value of his investments increased by $12 \%$ and $9 \%$ in the first year and the second year respectively. If the value of his investments after two years became ₹ $97,664$,then how much had he invested (in ₹)?

$A$ sum of money invested at simple interest for two years at $5 \% \text{ p.a.}$ amounted to $Rs. 2750$. The rate at which the sum should have been invested to get $Rs. 300$ as interest after two years would be (in $\%$)?