Question 2
The squares of a 3 by 3 table are labelled $1,2,\ldots,9$ as shown. In how many ways can we shade five of the squares so that no row or column is completely shaded?
Submission guidance: Give a full solution, as required for this even-numbered problem by the examination cover.
Submission guidance: Give a full solution, as required for this even-numbered problem by the examination cover.