I simplify a bit with placing the two men at the very ends and the middle man at the exact center of the log in line with its center of mass(considering log to have weight $W$). I know I have to find the normal reaction force on the middle man, suppose it to be $R$ and I know by solving moments that the normal reaction for two men on the sides are equal, both equal to suppose $F$. Now even if I solve using both resolving vertically and using moments I end with the same result of : $$2F+R=W$$ Even if I consider the two men at the ends to be not exactly at the ends but at a length $l$ from either side, we get using moments $2Fl+Rl=Wl$ which again ends up as $2F+R=W$.
So my question is, how did they get the result of the middle man having 25% more normal reaction force and if I'm missing any results here. Also, is it really possible to compare the normal reaction forces between the three men?