Question

A radiator contains 15 quarts of fluid, 30% of which is antifreeze. How much fluid should be drained and replaced with pure antifreeze so that the new mixture is 35% antifreeze? (Round your answer to two decimal places.)

Answer 1

%Antifreeze=VAntifreezeVFluid VFluid=VAntifreeze%Antifreeze VAntifreeze=Vfluid∗%Antifreeze I want to find the amount of antifreeze in a 15 quart solution with 30% antifreeze VAntifreeze=15∗0.30 =18/4 quarts of antifreeze Similarly, I want to find the amount of antifreeze in a 15 quart solution with 35% antifreeze first. VAntifreeze=15∗0.35 = 21/4 quarts of antifreeze


the difference between 21/4 and 18/4 is 3/4 quarts, which is the amount of pure antifreeze I've added in.

SO the V_fluid I replaced with 3/4 quarts of antifreeze is (3/4)/ 0.35