Question 518890
This would be my first solution here, so I may not be using the available tools fully.Any how:

LEE: covers 8 miles in T hours, this implies that his speed is: (8/T)miles/hour.

Sabrina: Covers 6 miles in T hours, this implies that her speed is: (6/T) miles/hour.

Now It is already told to us that the LEE speed is greater than Sabrina's speed by 1 miles/hour.

SO from above we get:

LEE Speed = Sabrina Speed + 1
8/T       =  6/T          +1

Solving for T gives T=2.
Hence LEE's speed is 4 miles/hour and Sabrina speed is 3 miles/hour.