A mixture of 125 gallons of wine and water contains 20% wine. How much wine must be added to mixture in order to increase the percentage of wine to 25% of the new mixture ?

8.33 gallons

Quantity of wine inthe mixture = 125 x \(\frac{20}{100}\) = 25

Let the quantity of wine to be added be x,

Then the quantity of water reduces to 75%

100 gallons of water = 75% of total mixture 

total mixture = 133.33 gallons

We need to mix, 

133.33 - 125 = 8.33 gallons of wine