I'm assuming you're asking for the elevator's final velocity.
Consider the following equation:
Vf = Vi + aΔt
Vf is the final velocity.
Vi is the initial velocity.
a is the acceleration.
Δt is the amount of elapsed time.
Given values:
Vi = 12.60m/s
a = -3.60m/s²
Δt = 2.97s
Substitute the terms in the equation with the given values and solve for Vf:
Vf = 12.60 - 3.60×2.97
Vf = 1.91m/s