Question

1 rupee interest means how much percentage

Answer 1

The answer of your question is  "1 percent"
So the 1  rupee interest means 1 rupee per 100 rupees.
interest is actually the percentage money you have to pay as the proportion of amount lent within a period . The interest per annual percentage is common for the money lent that is the amount of money a lender have to pay per year.it is actually the money lender charged to the borrower. 

Hope this helps,

Answer 2

1 rupee interest is calculated on the principal amount per month.

For example, if a person borrows 100 rupees at 1 rupee interest he has to pay 1 rupee interest every month. So he has to pay 12 rupees in 1 year.

Therefore, 1 rupee interest on 100 rupees means the percentage of interest is 12%.