Calling TT the tension on the rope, N_1N1 the normal force at the man floor, N_2N2 the normal force at the mass location, mu_sμs the friction coefficient, mm the man mass thetaθ the angle at the rope and gg the gravity, we have
Horizontally
T cos(theta)-mu_s N_1=0Tcos(θ)−μsN1=0
Vertically
N_1-m g + T sin(theta)=0N1−mg+Tsin(θ)=0 and T+N_2-M g=0T+N2−Mg=0
but at the problem conditions we have N_2=0N2=0 so we have
{(T cos(theta)-mu_s N_1=0),(N_1-m g + T sin(theta)=0),(T-M g=0):}
Solving for T,N_1,M we obtain
((T = (g m mu_s)/(Cos(theta) + mu_s Sin(theta))),(N_1 = (g m Cos(theta))/(Cos(theta) + mu_s Sin(theta))),(M = (m mu_s)/(Cos(theta) + mu_s Sin(theta))))
So finally
M = (m mu_s)/(Cos(theta) + mu_s Sin(theta))=34.9677