An I section beam of 4m length with end supports is required to carry a point load of 50 KN at its mid pint. The maximum bending stress is limited to 85 MPa, and Modulus of Elasticity of the steel s 200 GPa.

Evaluate maximum bending moment that will be applied, and state its position along the beam?

Really struggling with this for some reason.

I've ben shown that supports R1 and R2 at either end are 25 KN each

With a point load in the middle, draw the bending moment diagram, which is a triangle with zero at both ends, and linearly increasing to the middle at R1*L/2.

In fact, the standard formula for the maximum bending moment for a centrally placed point load is PL/4.
Review your notes for udl and other loads. They will be necessary for the rest of your career.