Quandaries and Queries


42.5 is what % of 170?

How do I work a problem like this?

Thank you,



Hi Dawn,

I like the way you have worded this question, "42.5 is what % of 170?" In this form I can directly change it to a mathematical statement (an equation) and then solve the equation.

In an equation the equal sign is the verb and is usually read "is" or "is equal to". Hence in your statement "42.5 is what % of 170?" the word "is" will become "=". In our use of English the word "of" is often multiplication. (For example 25 is one-quarter of 100.) Percent is per or over one hundred (cent come from the Latin word centum which means one hundred). The word "what" stands for the quantity you don't know. In mathematics we usually use a variable like x, or y, or z for the unknown quantity. I am going to use x. Thus

42.5 is what % of 170


42.5 = x/100 170

Solve for x.

To solve I would first multiply both sides by 100 to get

4250 = x 170

Now divide both sides by 170

 4250/170 = x


x = 25.

Thus 42.5 is 25% of 170.



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