CREATE TABLE table_47642 ("Year" FLOAT, "Championship" TEXT, "Winning score" TEXT, "Margin" TEXT, "Runner ( s ) -up" TEXT)

What is the winning score of the match with a margin of 3 strokes?
SELECT "Winning score" FROM table_47642 WHERE "Margin" = '3 strokes'
SELECT "Winning score" FROM "table_47642" WHERE "Margin" = '3 strokes'