At what rate per cent per annum will a sum of money double in $16$ years (in $.25$)?

$A$ 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 ₹):

The population of Mumbai increases by $5 \%$ per annum. Its population was $100000$ in $2004$. What was its population after $3$ years?

What principal will amount (in ₹) to ₹ $15000$ at $10 \%$ per annum in $5$ years?

If a certain sum of money amounts to ₹ $1760$ in $2$ years and ₹ $2000$ in $5$ years at simple interest,then the sum (in ₹) is:

When the rate of interest in a bank is reduced from $5 \%$ p.a. to $4.5 \%$ p.a.,Bani deposited $Rs. 4000$ in her savings account. She found that the new interest income remained the same as before. Find her original deposit (in $Rs.$)?