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?

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:

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

$A$ sum of ₹ $8000$ is divided into two parts. The simple interest on the first part at the rate of $21 \%$ per annum is equal to the simple interest on the second part at the rate of $35 \%$ per annum. What is the interest (in ₹) of each part?

In how many years will a sum of money treble itself at $10 \%$ per annum simple interest?

$A$ sum of money doubles itself in $8$ years. In how many years will it treble?