Equilibrium and find static friction

[PAstudent]

Homework Statement

Homework Equations

The Attempt at a Solution

I had someone help me with this problem (not on here) and their process and units don't seem to match to me. Or is this correct?

 

[haruspex]

That solution is clearly not right. It makes no use of the given dimensions, and these are easily seem to be relevant.
As required by the forum rules, please now post your attempt at a solution. Start with listing the standard equations you know which are likely to be relevant.