To determine how many minutes it takes Marcus to run 3 miles based on the points given on the graph, we first need to look at the pattern in the points provided:
- At (6, 1), it indicates that Marcus runs 1 mile in 6 minutes.
- At (12, 2), it indicates that he runs 2 miles in 12 minutes.
- At (18, 3), it indicates that he runs 3 miles in 18 minutes.
- At (24, 4), it indicates that he runs 4 miles in 24 minutes.
From the point (18, 3), we can see that Marcus can run 3 miles in 18 minutes.
So the correct response is: 18 minutes.