math
posted by Anonymous on .
a lab assistant wants to make 5 liters of 27.8% acid solutions. if solutions of 50% and 13% are in stock, how many liters of each must be mixed to prepare the solution?

just work with the amount of acid in each part. If there's x L of 50% acid,
.50x + .13(5x) = .278(5)
x=2