A lab assistant wants to make 5 liters of 27.2% acid solution. If solutions of 30% and 16% are in stock, how many liters of each must be mixed to prepare the solution?

Answer 1

amount of the 30% solution needed ---- x L
amount of the 16% solution needed --- 5-x L

.3x + .16(5-x) = .272(5)
times 100
30x + 16(5-x) = 136
30x +80 - 16x = 136
14x = 56
x = 4 L

4 L of the 30%, and 1 L of the 16% solution would be needed.