In a box, 10 smaller boxes were placed. Some of these boxes are empty, while others contain another 10 smaller boxes. Out of all the boxes, exactly 6 contain smaller boxes. How many empty boxes are there?
The solution to the problem did not pose a challenge to the majority of the solvers. The correct answer is 55. The largest box is not empty, as it contains 10 smaller boxes. Since exactly 6 boxes are not empty, 5 of the 10 smaller boxes are taken out. The other 5 smaller boxes each contain 10 empty boxes. Thus, the number of empty boxes is $5+5 \cdot 10=55$.