Oh yeah, from someone on level 11 it makes more sense that it was a typo in 'jego' and not in 'jej' ;) No problem, glad to help!
Oops sorry for the mistake its supposed to be jego.impressed with speedy reply.thanks
Why is it not ' on je jejo jablko' is it anything to do with his own apple.not actually sure when to use swoj swoja swoje etc.any help would be appreciated.
"Jejo" sounds as if you confused it with Russian её, I understand you meant "jej" - which would be 'her', 'hers'. Therefore you'd make it "He is eating her apple".
Basically, 'swój' and its forms are used when the pronoun goes back to the subject of the sentence - ergo, as you said, "his own apple". "On je jego jabłko" strongly suggests that he is eating some other guy's apple. "On je swoje jabłko" makes it absolutely clear that it is his own apple.