Mr. Gupta deposits ₹ $3000$ in a bank at $10 \%$ $p.a.$ and ₹ $5000$ in another bank at $8 \%$ $p.a.$. The rate of interest (in $\%$) for the whole sum is

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 for the first $2$ years is $3 \%$ per annum,for the next $3$ years is $8 \%$ per annum,and for the period beyond $5$ years is $10 \%$ per annum. If a man gets $Rs. 1520$ as simple interest for $6$ years,how much money (in $Rs.$) did he deposit?

In what time will ₹ $8100$ produce the same income at $3 \%$ as ₹ $225$ in $4$ years at $3 \%$?

What is the present worth (in ₹) of ₹ $132$ due in $2$ years at $5\%$ simple interest per annum?

$A$ sum of money becomes $\frac{8}{5}$ of itself in $5$ $years$ at a certain rate of interest. The rate per cent per annum is