math
posted by garrick on .
in her chemistry class, Lauren must produce 300ml of an 80% acid solution. Her teacher gives her two concentrations of acid solution, a 50% and a 100%. determine how much of each concentration that she must use.

.5x + 1y = .8(300)
x + y = 300
x = 300  y
.5(300y) + 1y = 240
150  .5y + 1y = 240
1/2y = 90
y = 180 ml
300180 = x = 120ml
use 120ml 50%
use 180ml 100%