This is the "masculine-singular in the oblique case." Often, the "masculine-singular in the oblique case" will look deceptively like "masc.-plural in direct case" since they will share the /e/ vowel. Therefore, it's imperative that we recognize if something is in the direct case or the oblique case.
के पास is a [two-word] post-position. It causes the preceding phrase to go into the "oblique case".
Let me know if you're unable to remember or locate the rules for the oblique case, and I'll elaborate!
is there a place in Duolingo where I can read theory_ So far I have relied on the discussion notes and mental analysis of my errors. Based on some notes in the discussions, my impression is that you guys also read theory. Is it in Duolingo or do you get to other sources_ Can someone help_ thank you.
In my humble opinion "हैं" is not because of the blique case but because the subject of the sentence: "three apples" is plural. The explanatory notes give the literal translation of such a sentence as: "Near my friend there are three apples" - hence "three apples" is the subject.
As a speaker of Hindi as a second language (I'm doing this course to (re)learn how to read, rather than to learn how to speak it) I don't think there is a difference between the two. My wife, a native speaker who's watching me do all these translations in mild ammusment, agrees & is actually the one who suggested "your friend has got three apples" as a more better\more literal translation.