Question

The boys mixed 10 gallons of 20% pure lemon juice mix and 10 gallons of the 70% pure lemon juice mix , because they wanted 20 gallons of lemonade at a 40%lemon juice mixture. They thought that because 40% was almost halfway between 20% and 70%,they should mix equal parts of both, but the lemonade turn out too tart. How much of each should they have used to get a final mixture of 20 gallons at 40% lemon juice?

Answer 1

If they used x gallons of 20% juice, then

.20x + .70(20-x) = .40*20
x = 12

so, 12 of 20% and 8 of 70%