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BEBRAS 2025 Grade 5-6 Round 2 Ext Question 7

BEBRAS · BEBRAS 2025 Grade 5-6 Round 2 Ext

Question 7

Alex wants to install the fewest security cameras for ten houses connected as shown. A camera at a house protects that house and every other house connected to it by one straight segment in the picture. For example, a camera at house 1 protects houses 1,2,3,4.

Question illustration

What is the minimum number of cameras needed to protect every house?
  1. 1
  2. 2
  3. 3
  4. 4