Hello there! The answer to this problem is that Bobby can run 4 miles in 28 minutes. If Bobby runs 1 mile in 7 minutes, we will have a table with two columns. On the left, we will have the number of miles, and on the right we will have the number of minutes.
miles - minutes
1 - 7
2 - 14
3 - 21
4 - 28
As the number of miles increases by 1, the number of minutes increases by 7. This is a ratio of 1:7. If it takes Bobby 7 minutes to run a mile, it makes sense that it will take him 28 minutes to run 4 miles because 28/7 = 4.
