You are not going to get penalised for structuring your URLs this way. Including the category ("apples" in this case) as a directory is a common, logical structure and enables the user to see the hierarchy in the URL.
I suspect your URL structure is as a consequence of your coding structure - is that right? And these particular pages are all within the "apples" category. In that case, including "apples" in the URL is acceptable. It doesn't matter how many pages are structured this way, whether it's 10's or 1000's. Google indexes pages; not websites. Including a repeating keyword in multiple pages (providing it's relevant to that page) does not matter.
Including "apples" and "apple" in the URL might be superfluous from an SEO point of view, but it's not detrimental to your keyword strategy.
Does the pathfile count as part of the keyword?
The whole URL can potentially influence SEO, however, it is just one metric that search engines might use to index your page.
how many words should a url be?
Nobody likes overly long URLs, but it perhaps it needs to be long enough to convey meaning. Looking at the stack exchange network as a prime example and this question in particular, there seems to be a limit of about 14 or 15 words - or perhaps whatever will fit within an 80 filename character limit?