SOLUTION: how many quarts of pure antifreeze must be added to 4 quarts of a 50% antifreeze solution to obtain a 60% antifreeze solution? (hint: pure antifreeze is 100% antifreeze) round to n
Algebra ->
Customizable Word Problem Solvers
-> Mixtures
-> SOLUTION: how many quarts of pure antifreeze must be added to 4 quarts of a 50% antifreeze solution to obtain a 60% antifreeze solution? (hint: pure antifreeze is 100% antifreeze) round to n
Log On
Question 1184175: how many quarts of pure antifreeze must be added to 4 quarts of a 50% antifreeze solution to obtain a 60% antifreeze solution? (hint: pure antifreeze is 100% antifreeze) round to nearest tenth as needed. Found 2 solutions by josgarithmetic, greenestamps:Answer by josgarithmetic(39618) (Show Source):
The response from the other tutor is not much help to a student who is trying to learn HOW to set up and solve this kind of problem....
Let x be the number of quarts of 100% antifreeze to add.
The antifreeze in the two ingredients is 100% of x quarts, plus 50% of the 4 quarts you started with; and it is 60% of the total (x+4) quarts:
Solve using basic algebra... I leave that to you.
If a formal algebraic solution is not required, here is a quick and easy way to solve any 2-part "mixture" problem like this.
Picture the percentages of the two ingredients and the final mixture on a number line -- 50, 60, and 100; observe/calculate that 60% is 1/5 of the way from 50% to 100%. (50 to 100 is a difference of 50; 50 to 60 is a difference of 10; 10/50 = 1/5.)
That means 1/5 of the mixture is the 100% antifreeze that you are adding.
So the 4 quarts you started with is 4/5 of the mixture; that means the 1/5 of the mixture that you added is 1 quart.
(