9514 1404 393
Answer:
450 L
Step-by-step explanation:
Let x represent the number of liters of 70% solution needed. Then the amount of 15% solution needed is (550-x), and the total amount of acid in the mixture is ...
0.70x + 0.15(550-x) = 0.60(550)
0.55x + 82.5 = 330 . . . . simplify
0.55x = 247.5 . . . . . . . . . subtract 82.5
x = 450 . . . . . . . . . . . divide by 0.55
450 liters of 70% acid solution must be used.
