Answer:
 W = 637 N
Step-by-step explanation:
For this exercise we will use Newton's second law 
 F -W = m a
 
where F is the force, m the mass and the acceleration 
in this case the force is the weight of the body and as the elevator goes at constant speed the acceleration is zero 
 F = W 
 a = 0 
 
 F = W 
 W = m g 
 W = 65 9.8 
 W = 637 N