Luke: 1 practice 1 lap, 2 practices 2 laps, 3 practices 3 laps, 4 practices 4 laps
Alex: 1 practice 3 laps, 2 practices 6 laps, 3 practices 9 laps, 4 practices 12 laps
Luke ran 3 laps for 3 practices, and Alex ran 9 laps for 3 practices.
Get all the n together so 3n+2n=5n
5n-17=38
Minus 17 from both sides
5n= 55
N= 11