A manufacturer of soft-drinks advertises that their orange soda as "naturally flavored," although it contains only 5% orange juice. A new federal regulation stipulates that to be called "natural" a drink must contain at least 10% fruit juice. How much pure orange juice must this manufacturer add to 900 gallons of orange soda to conform to the new regulation?

Answer 1

amount to be added --- x gallons

.05(900) + 1(x) = .1(900+x)
45 + x = 90 + .1x
.9x = 45
x = 45/.9 = 50