$A$ sum of money amounts to ₹ $9,800$ after $5$ $years$ and ₹ $12,005$ after $8$ $years$ at the same rate of simple interest. The rate of interest (in $\%$) per annum is

Rashmi lent $Rs. 600$ to Geeta for $2 \,yr$ and $Rs. 150$ to Seeta for $4 \,yr$ at the same rate of interest and received altogether $Rs. 80$ as simple interest from both. Find the rate of interest (in $\%$).

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

If a sum of money doubles itself in $8$ years at $S.I.$,then the rate of interest per annum (in $\%$) is: (in $.5$)

The rate of interest on a sum is $4 \%$ per annum for the first $2$ years,$6 \%$ per annum for the next $4$ years,and $8 \%$ per annum for the period beyond $6$ years. If the simple interest accrued by the sum for a total period of $9$ years is ₹ $1120$,find the sum. (In ₹)

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?