2.Mixture A is 15 percent alcohol, and mixture B is 50 percent alcohol. If the two are poured together to create a 4-gallon mixture that contains 30 percent alcohol, approximately how many gallons of mixture A are in the mixture?
Another approach for this question:
when combining liquids, I always use this rule: Vsum %sum = Va %a + Vb %b
put numbers from question into function
4 x 30/100 = Va x 15/100 + Vb x 50/100
Since Va+Vb=4; so Vb=4-Va
4 x 30/100 = Va x 15/100 + (4-Va) x 50/100
Anwser is C