Single or double-spaced?

Here's another question some of you are probably asking yourself:

Hi Dr. G,

I just read the blog about the page numbers ... I have been searching for a way to ask this question without sounding whinny, but can't figure out how to phrase it, so I figured I would just ask:
Do you mean 25 pages single spaced?

My reply:

Sorry ! That is important information -- and I forgot to give the word count, which makes more sense since we all like to use different fonts and margins. Let's say 15 pages (double-spaced)= 4,500 words and 25 pages = 7,500 words.