SELECT "Worst score" FROM table_70712 WHERE "Best score" = '36' AND "Worst dancer(s)" = 'john barnes'
What's the worst score for the worst dancer(s) john barnes, with a best score of 36?
CREATE TABLE table_70712 (
    "Dance" text,
    "Best dancer(s)" text,
    "Best score" real,
    "Worst dancer(s)" text,
    "Worst score" real
)