The monthly water bill is a function of the number of gallons used. The cost is $10.90 for 10,000 gal or less. Over 10,000 gal, the cost is $10.90 plus $1 for each 1000 gal over 10,000 with any fraction of
1000 gal charged at a fraction of $1. On what interval is the cost constant? On what interval is the cost increasing?
On what interval is the cost constant? Select the comect choice below and, if necessary, fill in the answer box to complete your choice.