Week 19

Four skiers - Dennis, Colton, Corbin, and Tyson - want to practice today. Practice sessions are from 8 to 10:40 A.M. only. Skiers must start the course 10 minutes apart and no more than 3 skiers may be on the course at once. Each skier is allowed to stay on the course for only 30 minutes. Can all 4 skiers practice today and finish before 9:40 A.M.?