Answer: They hike 30 miles and 20 miles in 1 hour respectively and they hike 60 miles and 40 miles in 2 hours respectively.
Explanation:
Since we have given that
Number of mile Jeff hikes in every 15 minutes =

As we know that
1 hour = 60 minutes
So, number of mile Jeff hikes in every 1 hour =

number of miles Jeff hikes in every 2 hours =

Number of miles Lisa hikes in every 10 minutes =

Number of miles Lisa hikes in every 1 hour =

Number of miles Lisa hikes in every 2 hours =

Hence, they hike 30 miles and 20 miles in 1 hour respectively and they hike 60 miles and 40 miles in 2 hours respectively.