Heather wants to make a 36% acid solution.She has already poured 31. oz. of a 72% acid solution into a beaker. How many ounces of a 9% acid solution must be add to this to create the desired mixture"?
0.72*31 + 0.09N =0.36*[31 + N], solve for N
N =124 / 3 = 41+1/3 oz. of 9% acid will be needed.
