Answer
given,
mass of the hiker = 66.5 kg
elevation of the hiker,h₁ = 1270 m
elevation of top peak,h₂ = 2660 m
a) Change in potential energy
Δ PE = m g h₂ - m g h₁
Δ PE = m g (h₂ - h₁)
Δ PE = 66.5 x 9.8 x (2660 - 1270)
Δ PE = 905863 J
b) Minimum work require by the hiker will be equal to Δ PE = 905863 J
c) yes, it can be more than this, if friction is present on the surface.