Im. lost plese i suck at unit rates

Luke: 2 miles in 40 minutes, 20 minutes a mile, (2/40 = 20 minutes a mile)
Luke's speed is 3 miles an hour (60minutes/20minutes a mile = 3miles).

Sally: 0.05 miles a minute, 60 minutes in an hour, 60 x 0.05 = 3 miles an hour.  Or 0.05 miles a minute, 40 minutes walked, 40 x 0.05 = 2 miles walked.

There are a few other ways to show that they are accurate rates. 

So yes, they are both correct rates.