Four workers, W, X, Y and Z, work at constant rates: W completes 2/5 of a task in 4 days, X completes 3/8 of the same task in 6 days, Y completes 5/9 of it in 5 days, and Z completes 3/4 of it in 9 days. If each worked alone on the full task at this same constant rate, who would finish first?