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BEBRAS 2025 Grade 9-10 Round 2 Ext Question 14

BEBRAS · BEBRAS 2025 Grade 9-10 Round 2 Ext

Question 14

Two fruit boxes X and Y each have ten numbered slots containing apples or oranges. In the original legend, Táo/A means apple and Cam/O means orange.

Question illustration

Move[m,n] swaps the fruits between X and Y in corresponding slots m through n, inclusive. Magic[m,n] changes each fruit in slots m through n of both boxes into the other type. Apply magic[5,7], then move[2,5], then magic[7,10]. How many more apples are then in X than in Y?
  1. 2
  2. 4
  3. 1
  4. 3