Happy Paws charges $19.00 plus $5.50 per hour to keep a dog during the day. Woof Watchers charges $11.00 plus $6.75 per hour. Complete the equation and solve it to find for how many hours the total cost of the services is equal. Use the variable h to represent the number of hours. Happy Paws cost equation: 5.50h + 19 Woof Watchers cost equation: 6.75h + 11 Set them equal to each other: 5.50h + 19 = 6.75h + 11 Using our equation solver, we get h = 6.4.