Mixture \(A\) is \(20\) percent alcohol, and mixture \(B\) is \(50\) percent alcohol. If the two are poured together to

Mixture \(A\) is \(20\) percent alcohol, and mixture \(B\) is \(50\) percent alcohol. If the two are poured together to create a \(15\)-gallon mixture that contains \(30\) percent alcohol, approximately how many gallons of mixture \(A\) are in the mixture?

(A) 3 gallons
(B) 4 gallons
(C) 5 gallons
(D) 10 gallons
(E) 12 gallons

Answer: D

Source: Veritas Prep