Pure acid is to be added to a 20% acid solution to obtain 52 L of a 40% acid solution

Answer 1

Let we took x L of pure acid and y L of 20% solution. Then x + 0.2y = 0.4·52 and 0.8y = 52·0.6.

From here y = 52·0.6/08 = 39 L, and x = 20.8 - 0.2·39 = 13 L.

Otvet: we have to add 13 L of pure acid