When doing this on a graph, you can just continue to plot the points until you reach the x-value of the point (x, 24). But there's an easier way to do that.
List what you know about the problem so far:
1 min = 2 gal
So, now that we know that, we can list what we need to solve:
x min = 24 gal
Now, you can simply divide 24 by 2 to get the number of minutes it would take to fill up 24 gallons.
24 ÷ 2 = 12
So,
x = 12
So,
12 min = 24 gallons
It would take 12 minutes to fill the 24 gallon holding pool. Which mean the coordinate point would be (12, 24).
Your answer should be B ) 12