CREATE TABLE table_68350 ("Name" TEXT, "Park" TEXT, "Country" TEXT, "Inversions" FLOAT, "Opened" TEXT, "Status" TEXT)

Name the sum of inversions for opened of april 20, 2002
SELECT SUM("Inversions") FROM table_68350 WHERE "Opened" = 'april 20, 2002'
SELECT SUM("Inversions") FROM "table_68350" WHERE "Opened" = 'april 20, 2002'