Table:
text: Hale Irwin
PGA Tour wins (20)
PGA Tour wins (20)
Date_ Tournament Winning_score To_par Margin_of_victory Runners_up
May 26, 1985 Memorial Tournament 72-67-68-67=274 −14 1 stroke Lanny Wadkins
Jun 18, 1990 U.S. Open 69-70-74-67=280 −8 Playoff Mike Donald
Jun 24, 1990 Buick Classic 66-69-68-66=269 −15 2 strokes Paul Azinger
Apr 17, 1994 MCI Heritage Golf Classic 68-65-65-68=266 −18 1 stroke Greg Norman

Question: If Hale Irwin's winning score is 68-65-65-68=266, what is his winning margin in PGA Tour wins (20)?

Question: On what date was Hale Irwin's winning score of the PGA Tour (20) (72-67-68-67=274)?