Do you believe in luck?

Well,for me this is a tricky to answer.To be honest, its kind of 50-50 situation to me.When i get fail in something then i think of luck,however when i get success i think its my hard-work which paid me . I would like to share an old incident which always forced me to think that luck exist in life.I had appeared for GK exam in my town along with my younger brother.Total no of participants were 100 .My brother who is 3 year younger to me ,got seat just next to me,might be luck factor. He had copied from me almost 50% of my answer sheet.I attempted 75 out of 100 qns. When result had announced ,i was shocked as i was ranked 3rd and my brother got 1st rank.How it was possible when he copied from me ? Luck? Smart? difficult for me to choose out of these two.He told me that not only he copied all answers from me but also attempted all 100 qns since there was no negative marking. Might be he was more smart keeping in mind those rules of marking or might be i was unlucky that he seated next to me ?