Consider the question. Erin works in the school cafeteria serving soup. Each bowl of soup has 10 ounces, and Erin can serve 5 bowls per minute. If the pot of soup has 6 gallons of soup, how long will it take Erin to serve all the soup, rounded to the nearest minute? (There are 128 ounces to a gallon.)
 What is the step-by-step reasoning process to arrive at the answer: 15?
First find the number of ounces Erin serves per minute: 10 ounces / bowl * 5 bowls / minute = 50 ounces / minute. Then find the number of ounces in the pot: 6 gallons * 128 ounces / gallon = 768 ounces. Then divide the total amount of soup by the amount of soup Erin serves per minute: 768 minutes / 50 ounces / minute = 15.36 minutes, which rounds down to 15 minutes.