The 24 ounce one ig because if you divide 7.50 by 15 you’ll find out that it’s 0.50€ per ounce. You’re saving money and getting more for the 25 pack because it should originally be $12.50 but they are giving you 10 more ounces for just $11.75
If the line is parallel, it has the same slope. So now just find the y intercept and put it into slope-intercept form