Answer
$2 \times 10^6 W$.
Work Step by Step
The work done on N skiers is the change in PE, N(mgh). Assume an average mass of 75 kg per skier. The power is the work done divided by time.
$$P=\frac{W}{t}=\frac{Nmgh}{t}=\frac{47000(75 kg)(9.80\frac{m}{s^2})(200 m)}{3600s} \approx 2 \times 10^6 W $$
