Question 235106
How many liters of water must be added to 10 L of 30% solution of antifreeze to reduce it to a 20% 
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There's 3 liters of a/f in the solution.
That 3 l will be 20% after adding water.
3 liters = 1/5 of the total
--> a total of 15 liters.
Add 5 liters of water.