A 70kg skier slides down a very slick (no friction) 25 degree incline for 50 meters. At the bottom of the slope he runs into a 50 kg youth skier who was standing still watching him. Trying to keep the young person from falling the skier grabs and holds on to him. They slide together across the flat but partially melted snow (some friction) a distance of 30 meters finally coming safely to rest. The softer level snow must have had a kinetic friction coefficient of (assume no loss of the skiers speed as he encounters the flat ground just before the collision)