You pick a fruit from the A+O box. Whatever it turns out to be is obviously what that bucket contains since it can't be A+O as the box is labeled incorrectly.
Let's say you picked an apple, making the A+O = apple. Your choices then are:
O = oranges or apples+oranges
A = oranges or apples+oranges
Since O can't be oranges, O = apples+oranges and A = oranges.
You pick a fruit from the A+O box. Whatever it turns out to be is obviously what that bucket contains since it can't be A+O as the box is labeled incorrectly.
Let's say you picked an apple, making the A+O = apple. Your choices then are:
O = oranges or apples+oranges
A = oranges or apples+oranges
Since O can't be oranges, O = apples+oranges and A = oranges.