If a certain sum of money borrowed at $5 \%$ per annum simple interest amounts to ₹ $1020$ in $4$ years,then the sum of money (in ₹) borrowed is:

If a sum of money at simple interest doubles itself in $6$ years,it will become four times in how many years?

Suhit borrowed a sum of $Rs. 6300$ from Vikas at the rate of $14 \%$ per annum for $3$ years. He then added some more money to the borrowed sum and lent it to Mohit at the rate of $16 \%$ simple interest for the same time. If Suhit gained $Rs. 618$ in the whole transaction,what sum did he lend (in $Rs.$) to Mohit?

$A$ 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 ₹):

In what time (in $years$) will ₹ $1200$ become ₹ $1344$ at $6 \%$ per annum simple interest?

The rate of interest on a sum of money is $4 \%$ per annum for the first $2$ years,$6 \%$ p.a. for the next $4$ years,and $8 \%$ p.a. for the period beyond $6$ years. If the simple interest accrued by the sum for a total period of $9$ years is ₹ $1120$,then the sum (in ₹) is: