Fluoridation is the process of adding fluorine compounds to drinking water to help fight tooth decay. A concentration of 1ppm of fluorine is sufficient for the purpose. ( 1ppm means one part per million, or 1g of fluorine per 1 million g of water.) The compound normally chosen for fluoridation is sodium fluoride, which is also added to some toothpastes. Calculate the quantity of sodium fluoride in kilograms needed per year for a city of 50,000 people if the daily consumption of water per person is 150 gallons. What percent of the sodium fluoride is "wasted" if each person uses only 6.0L of water a day for drinking and cooking? (Sodium fluoride is 45.0 percent fluorine by mass. 1 gallon =3.79L;1 year =365 days; density of water =1.0g/mL.)