Question 149143: How can I solve a proportion problem?
Answer by mangopeeler07(462)   (Show Source):
You can put this solution on YOUR website! For proportions, such as percentages, you would first set two fractions equal to each other, cross multiply and solve for the variable.
For example, if you are trying to find what percent of 60 is 20. You would set it up as:
20/60=x/100
x is over 100 because we don't know the percent. Then you would just cross multiply and solve.
20(100)=60x
2000=60x
33.3=x
If you know the percent but not the amount, for example what is 33% of 60? You would set it up as:
x/60=33/100
Cross multiply and solve.
100x=60(33)
100x=1980
x=19.8
If you know the percent and the amount, but not the denominator, as in 20 is 33% of what number? You would set it up as:
20/x=33/100
Cross multiply and solve.
20(100)=33x
2000=33x
60.6=x
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