Question: What was the margin of victory when the winning score was –10 (70-72-68-68=278)?
SQL: SELECT "Margin of victory" FROM "2-1552405-1" WHERE "Winning score" = '–10 (70-72-68-68=278)';

Question: When Gary Player was the runner-up, what was the margin of victory?
SQL: SELECT "Margin of victory" FROM "2-1552405-1" WHERE "Runner(s)-up" = 'Gary Player';

Question: In what tournament was the winning score –10 (68-71-69-70=278)?
SQL: SELECT "Tournament" FROM "2-1552405-1" WHERE "Winning score" = '–10 (68-71-69-70=278)';