SOLUTION: The radiator in a certain make of car needs to contain 30 liters of 40% antifreeze. The radiator now contains 30 liters of 20% antifreeze. How many liters of this solution must be
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-> SOLUTION: The radiator in a certain make of car needs to contain 30 liters of 40% antifreeze. The radiator now contains 30 liters of 20% antifreeze. How many liters of this solution must be
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Question 189821: The radiator in a certain make of car needs to contain 30 liters of 40% antifreeze. The radiator now contains 30 liters of 20% antifreeze. How many liters of this solution must be drained and replaced with 100% antifreeeze to get the desired strength? Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! The radiator in a certain make of car needs to contain 30 liters of 40%
antifreeze. The radiator now contains 30 liters of 20% antifreeze.
How many liters of this solution must be drained and replaced with 100%
antifreeze to get the desired strength?
:
Let x = amt of 20% solution to be drained, and also amt of 100% to be added
:
.2(30-x) + 1.0(x) = .4(30)
6 - .2x + 1x = 12
-.2x + 1x = 12 - 6
.8x = 6
x =
x = 7.5 liters to be removed and replaced
;
:
Check solution in original equation
.2(30-7.5) + 7.5 = .4(30)
.2(22.5) + 7.5 = 12
4.5 + 7.5 = 12
