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The word per cent may be in general interpreted to mean a `hundredth'. So e.g. 5 per cent is `5 hundredths', i.e.
 .
In practice, giving some number of per cents, one means so many hundredths of a quantity given in the same sentence or being clear from the context; for example, we can say that the illiteracy in the world is about 20 per cent - meaning that 20/100 of the adults of the world cannot read. If we say that the interest (rate) of a loan is 8 per cent, it means that one must pay interest for the loan 8/100 of the amount of the loan in a year.
If a percentage of a quantity has changed e.g. from 12% to 15%, we must not say that it has grown 3% but that it has grown 3 percentage points.
Determination of percentage
How many percent a number  is of a second number  ? The answer, the per cent number  , is obtained from
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(1) |
The number  here is called the base value and  the per cent value(?). Essentially, the procedure in (1) may be replaced by converting the ratio
 to hundredths, which can be done formally by multiplying this ratio by
 :
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