Question 1195288
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The other tutor has the correct answer of <u><font color=red>5 liters</font></u>.


Here's how to check it:
If 5 liters are poured out, then 80% of that is pure alcohol
80% of 5 = 0.80*5 = 4
So 4 liters of pure alcohol is poured out and 1 liter is water.


The 40 L of wine drops to 40-5 = 35 L after the wine is poured, but then we replace those five liters with water to get back to 35+5 = 40 L again.


The amount of pure alcohol is not replaced. We go from 0.80*40 = 32 L to 32-4 = 28 L


Then notice that 28/40 = 0.70 = 70%


Therefore, the answer has been confirmed.
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