Justin ran 15 miles at a constant rate in 2.5 hours. The next day, he ran at a rate that was 1 mph slower. What was Justin’s rate the second day?

We can use the factor label method for this problem. The real hint to these types of equations are the units. In this case the units are in miles per hour for the rate.
15 miles/ 2.5 hours = 6mph or 6 miles/hours
If his rate was 1 mph slower we just subtract 1 from 6 mph
6mph - 1mph= 5 mph.

Hope this helps, good luck.