The simple interest on a sum of money is $\frac{1}{9}$ of the principal and the number of years is equal to the rate per cent per annum. The rate per cent per annum is equal to

Reena took a loan of ₹ $1,200$ with simple interest for as many years as the rate of interest. If she paid ₹ $432$ as interest at the end of the loan period,what was the rate of interest?

$A$ sum of $Rs. 725$ is lent in the beginning of a year at a certain rate of interest. After $8$ months,a sum of $Rs. 362.50$ more is lent but at the rate twice the former. At the end of the year,$Rs. 33.50$ is earned as interest from both the loans. What was the original rate (in $\%$) of interest?

$A$ 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 ₹):

Two equal amounts are deposited in two banks,each at $15 \%$ per annum,for $3 \frac{1}{2}$ years and $5$ years respectively. If the difference between their interests is ₹ $1440$,each sum is (In ₹):

If a certain sum of money at simple interest amounts to ₹ $2800$ in $2$ $years$ and ₹ $3250$ in $5$ $years$,then the rate of interest (in $\%$) per annum is: