Given:Â
Mixture of vitamin water = 75% pure water & 25% concentrated vitamin drink. Â
To find:Â Â
Quantity of water to be added to 16 gallons of concentrated vitamin drink to prepare a tank of vitamin water. Â
Solution:Â
Let total amount of mixture be x.Â
25% of x = 16 gallons (from given information)Â Â
When 25% of x is 16 gallons, the remaining 75% of x will be calculated as below:
 (16/25)*75 = 48Â
 Answer: 75% of x = 48 gallons. This means 48 gallons pure water is required to be added to mixture to prepare a tank of vitamin water.