Question 562904
Solution A
Amount = x 
Concentration =15% = 0.15

Solution B
Amount = 30-x 
Concentration =40% = 0.40

Resultant Solution
Amount = 30 ounce 
Concentration =25% = 0.25

 
[Amount Solution A * Concentration A] + [Amount Solution B * Concentration of B]+ [Amount Solution B * Concentration of B] = Amount of Resultant * Concentration of resultant

x(0.15)+(30-x)(0.40)=(30)(0.25)
0.15x+12-0.4x=7.5
-0.25x=7.5-12
-0.25x=-4.5
-0.25x/-0.25=-4.5/-0.25
x=18





Solution A
Amount = x = 18
Concentration =15% = 0.15

Solution B
Amount = 30-x = 30-18 = 12
Concentration =40% = 0.40


18 ounces of 15% alcohol solution with a 12 ounces of 40% alcohol solution will be mixed to get 30 ounces of a 25% alcohol solution.