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1. The body text of the problem came without a question.
So, as I used to understand Math problems, this post is a nonsense.
2. Probably, they were going to ask about the total area which should be painted.
Or, probably, they were going to ask about the amount of paint needed.
I do not understand, why they hesitated to ask their question/questions.
3. But if they (or you) want to estimate the area to be painted, then calculate the areas of all walls, add them,
and then subtract the area of window, which you, as a reasonable person, are not going to paint (I suppose).
4. It is how I understand the problem.
5. Polya was a great mathematician, and created a worldwide known problems book in mathematical analysis.
(Many years ago, I got two volumes of this problems book as a prize / (an award) for my winning in Math Olympiad from the organizers.)
Polya was a great teacher, too, but he never vent down to discuss such trivial level problems.
His the entire life's task was to move his students forward and UP -- not backward and down,
as this problem (and its author) tries to do.