Answer:
= 1.25 m
Step-by-step explanation:
mass of man (Mm) = 60 kg
mass of board (Mb) = 20 kg
length of board (L) = 10 m
Firstly lets take the center of the board as our origin, this means that the center of the board will be x = 0 and the man will be standing at one end of the board which will be point x = 5. Therefore:
Point of action of boards mass (P1) = 0 m
Position of the man (P2) = 5 m
center of mass =

center of mass =

center of mass = 300 / 80 = 3.75
this means the total center of mass of the man-board system is at 3.75 m from the origin.
The distance of the center of mass from the position of the man = 5 - 3.75
= 1.25 m