Answer:
16 quarts
Step-by-step explanation:
Let's say x is the volume of water.
Initially, the amount of antifreeze is the concentration times the volume: 0.90 (8).
After the water is added, the amount of antifreeze is the new concentration times the new volume: 0.30 (8 + x).
Since the amount of antifreeze doesn't change, we can set these equal and solve for x.
0.90 (8) = 0.30 (8 + x)
7.2 = 2.4 + 0.30 x
4.8 = 0.30 x
x = 16
16 quarts of water should be added.
