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?
We need 5 liters of 27.2% acid A) x + y = 5 B) .30 x + .16y = 5 * .272 Multiplying A by -.30 A) -.30 x - .30y = -1.5 then adding to B B) .30 x + .16y = 1.36 -.14y = -.14 y = 1 liter 16% x = 4 liters 30%
