Help! 

My name is GiGi Page.  I believe my question could fall into either the middle or secondary level.  I am not a teacher or student-just someone who has forgotten how to calculate some basic percentages.  My question is:

What formula would I use to calculate the following:  What percentage of 6 billion is 40 million? 

Any information will be greatly appreciated. 
Thank you!  GiGi

Hi GiGi,

You have done much of the work by asking the question is such a precise way

What percentage of 6 billion is 40 million? 

There is a straightforward method that I use to change this into an algebraic expression which I can then solve.

• What is the unknown quantity. In algebra we usually give it a symbol like x or y.
• percent is "per one humdred", that is divided by 100.
• "of" is multiplication, like "half of 6 is 3".
• "is" is the verb. Think of some mathematical formula and read it to yourself. The verb is the equal sign.

Thus you expression

What percentage of 6 billion is 40 million? 

becomes

 ^x/₁₀₀  6,000,000,000 = 40,000,000

To solve this equation first multiply both sides br 100. The equation becomes

x 6,000,000,000 = 4,000,000,000

Nuw divide both sides by 6,000,000,000 to get

x = ^{4,000,000,000}/_{6,000,000,000} = ⁴/₆ = 0.667

Thus 40 millioin is 0.667 percent of 6 billion.

Penny

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