Math CentralQuandaries & Queries


Question from Nick, a teacher:

Based on the estimate of the worlds current population (7.3 billion people), I'm trying to work out what percentage of that figure 20 million people would amount to?

(Apologies in advance that I've no idea if the 7.3 billion figure is an American Billion or UK billion)

Thanks for any help.


Hi Nick,

Look at my note More on Millions and Billions about the meaning of billions.

Since a billion is $10^9 = 1,000,000,000$ and a million is $10^6 = 1,000,000,$ 20 million as a percentage of 7.3 billion is

\[\frac{20,000,000}{7,300,000,000} \times 100 \mbox{ percent.}\]


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