26. For his job delivering pizzas, Albert uses his own car and buys his own gas. He joined the local gas station’s Frequent Fueler program that earns him points toward free gas each time he buys gas. Points are earned according to the following chart.

Frequent Fueler Program:

Sign up for the program, earn 50 points

Buy 1 gallon regular, earn 3 points

Buy 1 gallon premium, earn 4 points

At the end of his first month in the program, he received a statement showing that he had 545 points (including 50 points he received for signing up) and had purchased a total of 135 gallons of gas. To find how many gallons of premium he had purchased, he solved a system of equations with r representing the number of gallons of regular and p representing the number of gallons of premium. One equation in his system was r + p = 135. Which of the following could have been his other equation?