A Guide to the GRE/Percentages

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Percentages[edit | edit source]

Percentage is a fraction of 100. 11% = .11 =

Percent simply means “per hundred.” However, be careful not to mix up the two key ways in which percentages are used.

Do not mix up changing to a percentage with changing by a percentage.

If a group of 100 members decreases to 20% of its membership, its membership goes down to 20. If the group decreases by 20%, it goes down to 80. Increasing to 110% is the same as increasing by 10%. This also applies to fractions and decimals but is an especially common error with percentages.

Practice[edit | edit source]

1 What is 30% of 80?

(Questions 2-3) If a bank account worth $10,000 increased in value by 25%...

2 ...how much did it increase?


3 ...how much is it worth now?


(Questions 4-5) If a bank account worth $10,000 decreased in value to 25% of its worth...

4 ...how much did it decrease?


5 ...how much is it worth now?