Rakesh borrowed ₹ $5000$ from Ganesh at simple interest. If Ganesh received ₹ $500$ more than his capital after $5$ years,then the rate of interest (in $\%$) per annum is:

Nutan invests $Rs. 22400$ at a Simple Interest $(S.I.)$ rate of $12$ $p.c.p.a.$ How much amount will she receive after $7$ years (in $Rs.$)?

David invested a certain amount in three different schemes $A, B$ and $C$ with the rate of interest $10 \% \text{ p.a.}, 12 \% \text{ p.a.}$ and $15 \% \text{ p.a.}$ respectively. If the total interest accrued in one year was ₹ $3200$ and the amount invested in scheme $C$ was $150 \%$ of the amount invested in scheme $A$ and $240 \%$ of the amount invested in scheme $B$, what was the amount (in ₹) invested in scheme $B$?

In what time (in $years$) will a sum of money double itself at the rate of $20 \%$ per annum simple interest?

Sapna borrowed a certain sum of money from Kavita under the following repayment scheme based on simple interest: $8 \%$ $p.a.$ for the initial $2$ $years$,$9.5 \%$ $p.a.$ for the next $4$ $years$,$11 \%$ $p.a.$ for the next $2$ $years$,and $12 \%$ $p.a.$ after the first $8$ $years$. Find the total amount (in $Rs.$) which a sum of $Rs. 9000$ taken for $12$ $years$ becomes at the end of $12$ $years$.

$A$ certain sum is invested for $T$ years. It amounts to ₹ $400$ at $10 \%$ $p.a.$. But,when invested at $4 \%$ $p.a.$,it amounts to ₹ $200$. Find the time (in years) $(T)$.