A man thinks to remain in equilibrium by pushing his hands and feet against two vertical

            paralleled walls.

            1) He must exert equal forces on both walls

            2) The forces of friction at both walls must be equal

            3) Friction must be present on both walls

A man thinks to remain horizontally in equilibrium against two vertical walls as

shown the requirement is weight w= $f_1+f_2$

To fulfill the requirement he has to push both walls with same force F and should avail

            horizontal component of reaction force (F) as frictional forces

            $f_1={f_2}_{ }$

            So there must present friction on both walls

            i.e. the wall must have rough surface.

            So among the given statements we have 1 and 3 as correct