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In a 9-cell square (3x3 with 9 cells) more than 7 are painted yellow and more than 5 are painted blue. If a cell is painted yellow and blue, then it is resulting in green. In the end, all the cells in the square painted.

How many green cells are there?

So, there must be 8 yellow and 6 blue cells (minimum for both)

In that case I see to possible outcomes:

  1. There are 5 green and one square has only blue and not yellow.
  2. There are 6 green.

According to the answer key, there are only 3 green squares.

What is going on here?

Zeta10
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    My guess is that when they wrote "more than X" they actually meant "X or more". Indeed, if there are $7$ yellow and $5$ blue cells, there must be at least $3$ green cells. ($x$ green cells with $7-x$ yellow and $5-x$ blue cells gives you $12-x\le 9$ cells, implying $x\ge 3$.) –  Dec 31 '22 at 10:05
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    Probably here "more than" means $\geq$ (instead of $>$). Is the original statement written in english? – Robert Z Dec 31 '22 at 10:07
  • @RobertZ it is written in English. But, not sure about that. If there are precisely 7 yellow and precisely 5 blue, then it leads to necessarily 3 green. – Zeta10 Dec 31 '22 at 10:15
  • 7 yellow and 5 blue could yield 3, 4, or 5 green. – MJD Dec 31 '22 at 13:47

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