5. A football is sewn from 256 pieces of leather: white ones in the shape of hexagons and black ones in the shape of pentagons. Black pentagons only border white hexagons, and any white hexagon borders three black pentagons and three white hexagons. Find the number of white hexagons on the football.
Answer: 160.

Criteria for checking works, 7th grade

Preliminary round of the sectoral physics and mathematics olympiad for schoolchildren "Rosatom", mathematics

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