The radiator in a car is filled with a solution of 65% antifreeze and 35%t water. The manufacturer of the antifreeze suggests that for summer driving, optimal cooling of the engine is obtained with only 50% antifreeze. If the capacity of the raditor is 3.6 liters, how much coolant (in liters) must be drained and replaced with pure water to reduce the antifreeze concentration to 50%?

Let x = the amount of coolant to be drained.

Balance by the amount of solute:

(3.6-x)(.65) = 3.6(0.5)

Solve for x,

x = (3.6)(.6)/(.65)=3.323 liters

## Comments

The radiator in a car is filled with a solution of 65 per cent antifreeze and 35 per cent water. The manufacturer of the antifreeze suggests that for summer driving, optimal cooling of the engine is obtained with only 50 per cent antifreeze. If the capacity of the raditor is 3.6 liters, how much coolant (in liters) must be drained and replaced with pure water to reduce the antifreeze concentration to 50 per cent?