Question 311512
how much acid 90% pure must be added to 15 0z. of 60% acid to make a mixture which is 75% pure
.
Let x = amount of 90% acid added
then
.90x + .60(15) = .75(x+15)
.90x + 9 = .75x+11.25
.15x + 9 = 11.25
.15x = 2.25
x = 15 Oz.