He scored 42 goals in the last 3 seasons, while playing for many games (I would say most of them) as No.10. On the two recent seasons he played as No.1 he scored 26, respectively 27 goals. I am not saying that he'll repeat that, but 17 goals per season isn't beyond Rooney's ability.I just can't see him scoring 50 for us over the next 3 seasons, furthermore a 36 year old Rooney still knocking in 10 goals a season?
He probably won't get 50, but very likely he'll get 40 league goals in the next 3 seasons. Won't be enough to threaten Shearer's record though.