9514 1404 393
Answer:
1.1 quarts
Step-by-step explanation:
Let x represent the amount to be added, in quarts. Then the amount of anti-freeze in the resulting solution is ...
0.20(8) + 1.00(x) = 0.30(8 +x)
0.70x = 0.10(8) . . . . . . subtract 0.20(8)+0.30(x)
x = 8/7 . . . . . . . . . . . . . divide by the coefficient of x
x ≈ 1.142857 ≈ 1.1
About 1.1 quarts of pure antifreeze must be added.
