How do you go about solving this problem?

Question

Two snowy peaks are h = 850 m and 750 m above the valley below. A ski run extends down from the top of
the higher peak and then back up to the top of the lower one, with a total length of 3 km and an average slope
of 30°. A skier starts from rest on the higher peak. If the snow is slick so that friction may be neglected, at
what speed will he arrive at the top of the lower peak if he just coasts without using his poles?

Answer 1

Potential energy is partitioned into kinetic and potential once it reaches the second hill.

PE=mgh

PE=PE1+KE2

mgh=mgh'+1/2mv^2
gh=gh'+1/2v^2
gh-gh'=1/2v^2
2g(h-h')=v^2
v=sqr[2g(h-h')]
v=sqr[2*9.81(850-750)]
v=44.3 m/s

Answer 2

Use conservation of Energy. The energy of the skier is conserved, since friction is neglected, and it is the potential energy plus the kinetic energy.