"Ella ya ha leído el mismo libro más de quince veces."
Translation:She has already read the same book more than fifteen times.
If I had written the sentence, I might have used "mas que" instead of "mas de". Is there a rule for "de" vs "que".
‘más de’ is only used with quantities. In positive sentences, ‘más que’ is not used with quantities. In negative sentences, both are acceptable.
Yes, there is. más de = more than. más que, usually used in negative sentences, no más que = no more than. So más de could be anything over 15, whereas no más que = anything 15 and under. Have I sufficiently confused you?
Yes :) I think I have heard terms such as "mas que yo" or "mas que el" without it being a negative.
Instead of all that was said above - here is a reference that covers exactly why. http://spanish.about.com/od/sentencestructure/a/mas_que_de.htm