Terrance and jesse are training for a long-distance race. terrance trains at a rate of 6 miles every half hour, and jesse trains at a rate of 2 miles every 15 minutes

1. what is the unit rate in miles per hour for each runner?

2. how long will each person take to run a total of 50 miles at the given rates?

3. sandra runs at a rate of 8 miles in 45 minutes. how does her unit rate compare to terrance's and to jesse's?