SOLUTION: A radiator contains 5 quarts of fluid, 10% of which is antifreeze. How much fluid should be drained and replaced with pure antifreeze so that the new mixture is 50% antifreeze?

Question 911642: A radiator contains 5 quarts of fluid, 10% of which is antifreeze. How much fluid should be drained and replaced with pure antifreeze so that the new mixture is 50% antifreeze?
Found 2 solutions by josgarithmetic, richwmiller:
Answer by josgarithmetic(39617) (Show Source): You can put this solution on YOUR website!
That is a very common type of exercise question and a lesson for it is here:

Drain and Replace: Radiator Antifreeze Mixture - http://www.algebra.com/my/drain-and-replace-antifreeze.lesson?content_action=show_dev
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
0.1*5-0.1x+1x=0.5(5)
0.5+0.9x=2.5
0.9x=2.5-0.5
0.9x=2
x=2.22222222
check
0.1*2.77777778+1*2.22222222=0.5(5)
0.27777778+2.22222222=2.5
2.5=2.5
ok
coderep

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