The Hydro water department has a monthly service charge of $10.10 and a volume charge of $1.58 for every 100 cubic feet of water. The total monthly cost is equal to the service charge plus the charge for the volume used during the month. If we let x represent the number of cubic feet of water (in hundreds) and y represent the total monthly cost, then we have: total monthly cost = volume charge + service charge y = 1.58x + 10.10 If the Johnson family used 200 ft3 less water this month than last month, then they can expect A. an increase in their water bill of $3.16. B. a decrease in their water bill of $3.16. C. a decrease in their water bill of $20.20. D. an increase in their water bill of $20.20.