Answer
(a) $W=24320J$
(b) $W=-10412J$
Work Step by Step
The formula to find work is $$W=(F\cos\theta)s$$
(a) Since the elevator goes at a constant velocity, the normal force exerted on you and your belongings by the elevator equals the total weight of you and your belongings: $$F_N=\sum W=685N+915N=1600N$$
Here $\theta=0$ and the magnitude of displacement $s=15.2m$, so $$W=(F_N\cos0)s=F_Ns=24320J$$
(b) On the downward trip, the normal force exerted on you by the elevator equals your weight, since the elevator still goes at a constant velocity: $$F_N=685N$$
We have $s=15.2m$, $F_N$ points upward while the elevator goes downward so $\theta=180^o$, so $$W=(F_N\cos180)s=-F_Ns=-10412J$$
