A technician needs 12 liters of a 30% acid solution. She has an unlimited supply of a 25% acid solution and an unlimited supply of a 40% acid solution. How many liters of each solution should she use?

Answer 1

X + Y = 12

acid concentration is:

0.25x + 0.4y = 12*0.3 = 3.6

y = 12-x

25x + 40y = 360

25x + 40(12-x) = 360

25x + 480 - 40x = 360

480 - 15x = 360

-15x = -120

x = 8

Y=4