What time (in years) is taken by a sum of $Rs. 7000$ to become $Rs. 10500$ at the rate of $5 \%$ per annum simple interest?

$A$ sum of $Rs. 1521$ is lent out in two parts in such a way that the simple interest on one part at $10 \%$ for $5 \,yr$ is equal to that of another part at $8 \%$ for $10 \,yr$. What will be the two parts of the sum?

$A$ man invested $\frac{1}{3}$ of his capital at $7 \%$,$\frac{1}{4}$ at $8 \%$,and the remaining at $10 \%$ rate of simple interest. If his annual income from interests is ₹ $561$,then the total capital invested (in ₹) was:

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 money lent out at simple interest amounts to $Rs. 720$ after $2$ years and $Rs. 1020$ after a further period of $5$ years. Find the principal (in $Rs.$).

Dalajit lent ₹ $10800$ to Jaabir for $3$ $years$ and ₹ $7500$ to Kabir for $2$ $years$ on simple interest and received ₹ $1422$ in all from both of them as interest. The rate of interest (in $\%$) per annum is