A paint company mixes it's paint with water to create more paint per gallon. They currently have ten gallon jugs which contain 10% water. How much water must they add to create a 80/20 mix of paint to water?

1 gallon
1.25 gallons
1.5 gallons
1.75 gallons
2 gallons

http://www.4tests.com/exams/questions.asp?qid=3919&nqid=3919&rev=1&dir=v&exid=16935326&qc=13