Pure acid is to be added to a 5% acid solution to obtain 95L of 9% solution. What amounts of each should be used?

Answer 1

Let P = amount of pure acid

Let S = amount of acid in 5% solution

1P + 1S = 95 (95 L of mixture)

1P + .05S = .09 (95) = 8.55 (mixture is 9% acid)

Subtract the bottom line from the top line

.95S = 95 (1 - .09)

S = 91

P = 4