Solve the problem.
-It is necessary to have a 40% antifreeze solution in the radiator of a certain car. The radiator now has 30 liters of 20% solution. How many liters of this should be drained and replaced with 100% antifreeze to get the desired strength?
A) 15 L
B) 12 L
C) 10.0 L
D) 7.5 L

Question

Quizplus · Accepted Answer

To achieve a 40% antifreeze solution, we can use the equation: (amount of antifreeze initially + amount of antifreeze added) / total solution = desired concentration. Initially, there are 30 liters of a 20% solution, so there are 30 * 0.20 = 6 liters of antifreeze. Let x be the amount to drain and replace with 100% antifreeze. The amount of antifreeze after replacement is (6 - 0.20x + x). The total solution remains 30 liters. Setting up the equation: (6 - 0.20x + x) / 30 = 0.40. Solving for x gives x = 7.5 liters.

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