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:

Gaurav borrowed $Rs. 800$ at $6 \%$ and Naresh borrowed $Rs. 600$ at $10 \%$. After how much time will they both have equal debts?

What is the interest (in $Rs.$) received on a principal of $Rs. 450$ for $2$ years, if the interest received on $Re. 1$ after $4$ years at the same rate of simple interest is $Rs. 0.40$?

Alipta received some amount of money from her father. In how many $years$ will the ratio of the money (principal) and the interest obtained from it be $10: 3$ at the rate of $6 \%$ simple interest per annum?

₹ $1500$ is invested at a rate of $10 \%$ simple interest,and the interest is added to the principal after every $5$ years. In how many years will it amount to ₹ $2500$?

$A$ sum of money will double itself in $16$ years at simple interest at an yearly rate of (in $\%$):