The amount w of water used varies directly with the population 'n' of people. city 'a' has a population of 483,000 people and used 37.6 billion gallons of water in a fiscal year. find out how many billion gallons of water we would expect city 'b' to use if we know that its population is 150,000 w= billion of gallons of water type an integer or decimal rounded to the nearest tenth as needed.