Word Problems

How many liters of a 67% sulfuric acid solution must be added to 3 liters of a 27% solution of sulfuric acid to obtain a 42% solution of sulfuric acid?
s = the # of liters of sulfuric acid we will add
In the equation we will identify the amount of acid in each fluid.

67%s + 27%(3 liters) = 42% (3 liters + s liters )
.67s +.27(3) = .42(3) + .42 s
.67s + .81 = 1.26 + .42s
.67s - .42s = 1.26 - .81
.25s = .45
s = .45 ÷ .25
s = 1.8
Therefore approximately 1.8 liters of 67% sulfuric acid solution must be mixed with the 3 liters too make the 42% mixture.

return