First your homework: read Do bigger skiers go faster?

From that article, the magnitude of the acceleration of a skier of mass m travelling straight down a slope of angle θ is

a = g sinθ -μg cosθ -kA/m

where g is the gravitational constant, μ is the coefficient of friction between ski and snow, and kA is a constant related to the coefficient of drag of the skier (air resistance).

Contrary to what you might think, the frictional term μg cosθ does not depend on the length or area of the ski in contact with the snow.

So, all other things being equal (same skier, same slope, same conditions), wider/longer/bigger skis  don’t go any faster or slower.