Because the slope doesn't tell you any actual points on the line. It only tells you whether the line tilts up or down, and how steeply. But the line could be way up there or way down under, with the same slope. You can't actually DRAW it until you know some point on it, and the y-intercept gives you one.
First off Jackson's mom sucks for limiting game time and second of the answer is 30 minutes. If 9 is 30 percent that means 3 is 10 percent. 3 times 10 is 30. So 30 minutes
