Answer:
70kg
Step-by-step explanation:
Given parameters: 
Gravitational force = 700N
Unknown: 
Mass of the person = ? 
Solution: 
The weight is gravitational force on the person and can be expressed as; 
 W = mg 
m is the mass 
g is the acceleration due to gravity = 10m/s² 
 So;
 700 = m x 10 
 m = 70kg