Prakash lends a part of ₹ $20,000$ at $8 \%$ simple interest and the remaining at $\frac{4}{3} \%$ simple interest. His total income after a year was ₹ $800$. Find the sum (in ₹) lent at $8 \%$ interest.

Simple interest received by a person in $10$ $years$ on a principal of ₹ $9500$ is $130 \%$ of the principal. What is the rate of interest (in $\%$) per annum?

For what sum (in ₹) will the simple interest at $R \%$ per annum for $2$ years be $R$?

If $A$ borrowed $₹P$ at $x\%$ and $B$ borrowed $₹Q$ $(Q > P)$ at $y\%$ per annum at simple interest at the same time,then the amount of their debts will be equal after:

$A$ man invests a certain sum of money at $6 \%$ $p.a.$ simple interest and another sum at $7 \%$ $p.a.$ simple interest. His income from interest after $2$ $years$ was $Rs. 354$. One-fourth of the first sum is equal to one-fifth of the second sum. Find the total sum (in $Rs.$) he invested.

$A$ certain sum of money amounts to ₹ $2200$ at $5 \%$ $p.a.$ rate of interest,and ₹ $2320$ at $8 \%$ interest in the same period of time. The period of time (in years) is: