jet1445 wrote:

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?

A. 1.5

B. 1.7

C. 2.3

D. 2.5

E. 3.0

Another approach for this question:

when combining liquids, I always use this rule:

Vsum %sum = Va %a + Vb %b
Note: V=volumn

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

Va=2.3

Anwser is

C