Solve the problem.
-It is necessary to have a 40% antifreeze solution in the radiator of a certain car. The radiator now has 50 liters of 20% solution. How many liters of this should be drained and replaced with 100%
Antifreeze to get the desired strength?
A) 12.5 L
B) 25 L
C) 16.7 L
D) 20 L

Question

Quizplus · Accepted Answer

To achieve a 40% antifreeze solution in the radiator, you need to replace a portion of the 20% solution with a 100% antifreeze solution. The amount of pure antifreeze in the original mixture is 20% of 50 liters, which is 10 liters. To make the entire mixture 40% antifreeze, you need 40% of 50 liters, which is 20 liters of pure antifreeze. Therefore, you need to add 10 more liters of pure antifreeze to the radiator. Since you are adding 100% antifreeze to replace the drained solution, the volume you add will also be the volume you drain. Thus, you need to drain 12.5 liters of the 20% solution and replace it with 12.5 liters of 100% antifreeze to achieve the desired 40% solution.

Solve the Problem. -It Is Necessary to Have a 40% Antifreeze Solution in Antifreeze