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UKMT Grey Kangaroo, 2021

Combinatorics Difficulty 2.0 Junior Find the answer United Kingdom

A ball is made of white hexagons and black pentagons, as seen in the picture. There are 12 pentagons in total. How many hexagons are there?

(A) $12$ (B) $15$ (C) $18$ (D) $20$ (E) $24$

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