The least number of complete years in which a sum of money put out at $20 \%$ compound interest will be more than doubled is

$A$ man borrows money at $3 \%$ per annum interest payable yearly and lends it immediately at $5 \%$ interest (compound) payable half-yearly and thereby gains ₹ $330$ at the end of the year. The sum borrowed (in ₹) is

The difference between simple interest and compound interest on a certain sum for $3$ years at $5 \%$ per annum is ₹ $122$. Find the sum (in ₹).

The difference between the compound interest and the simple interest on ₹ $8000$ for $3$ years at $5 \%$ per annum is (in ₹):

Monica deposited a total of $Rs. 10500$ with a bank in two different deposit schemes at $10 \%$ $p.a.$,interest being compounded annually. As per the schemes,she gets the same amount after $2 \,years$ on the first deposit as she gets after $3 \,years$ on the second deposit. How much money (In $Rs.$) did she deposit for $3 \,years$?

At what rate per cent compound interest does a sum of money become $16$ times in $4$ years?