A 9-Quart Cooling System Is Checked and Found to Be

Multiple Choice

A 9-quart cooling system is checked and found to be filled with a solution that is 10% antifreeze. The desired strength of the solution is 70% antifreeze. How many quarts of solution need to be drained and replaced with pure antifreeze to reach the desires strength?

A) 8 qt
B) 7 qt
C) 10 qt
D) 6 qt
E) 13 qt