In the 2014-15 standards document, in the general notes for the probability section there is the statement:

Teachers should be aware that specific outcomes 4, 5, and 6 do not require the simplification of factorial expressions (e.g. Simplify n! / (n - 2)! ).

This note was not included in the 2012-13 standards document.

I think solving equations like nP2=12 and nC2=45 are appropriate, but guessing and testing values is a satisfactory solution. I think the pathways problem is appropriate, but I don't think they'll see the case of overlapping rectangles