Question 600388
let 20% sulfuric acid = x grams


20/100 * x + 35/100 * 20 = 26/100 * (x + 20)
0.2x + 7 = 0.26*(x + 20)
0.2x + 7 = 0.26x + 5.2
7 - 5.2 = 0.26x - 0.2x
1.8 = 0.06x
x = 1.8/0.06 = 180/6 = 30


so the 20% sulfuric acid needed is 30 grams