$A$ 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 ₹):

$A$ sum was put at simple interest at a certain rate for $2$ years. Had it been put at $1 \%$ higher rate,it would have fetched ₹ $24$ more. The sum is (in ₹):

$A$ certain sum becomes $5$ times in $3$ years at simple interest. In how many years will it become $13$ times?

Peter invested an amount of ₹ $12,000$ at the rate of $10 \%$ $p.a.$ simple interest and another amount at the rate of $20 \%$ $p.a.$ simple interest. The total interest earned at the end of one year on the total amount invested became $14 \%$ $p.a.$ Find the total amount (in ₹) invested.

What is the $S.I.$ on $Rs. 800$ at $5 \%$ per annum for $3$ years?

$A$ certain sum becomes ₹ $1020$ in $5$ years and ₹ $1200$ in $8$ years at simple interest. What is the value of Principal (in ₹)?