Skip to content / Đến nội dung
ThichHocToan.com

BEBRAS 2019 Grade 9-10 Round 2 Ext Question 1

BEBRAS · BEBRAS 2019 Grade 9-10 Round 2 Ext

Question 1

Ada has a box of ten pencils. A box is beautiful when all pencils point in the same direction. In one move she reverses one contiguous group: upward pencils become downward and downward pencils become upward, as in the example.

Question illustration

What is the minimum number of moves needed for this box?

Question illustration
  1. 1 move
  2. 2 moves
  3. 3 moves
  4. 4 moves