A 80 kg skier grips a moving rope that is powered by an engine and is pulled at constant speed to the top of a 21 hill. The skier is pulled a distance z = 240 m along the incline and it takes 2.3 min to reach the top of the hill. If the coefficient of kinetic friction between the snow and skis is = 0.12, what horsepower engine is required if 30 such skiers (max) are on the rope at one time? Express your answer using two significant figures.