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Tiles

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by adilka » Mon Jan 12, 2009 5:27 pm
100 white and black tiles will be used to form a 10x10 square pattern. There must be at least one black tile in every row and at least one white tile in every column. What is the maximum difference between the numbers of black and white tiles that can be used?

75
80
85
90
95

I made an uber-brainfart on this one! How many more will do it? OA Later
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Re: Tiles

by logitech » Mon Jan 12, 2009 5:51 pm
So MAX Black - MIN white

If the white are placed as the diagonal, we will need only 10 White so the rest can be Black 90

And the difference = 80 ?
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by Mr2Bits » Mon Jan 12, 2009 5:55 pm
I get B.

10X10 is 100 tiles.

10 on white diagnal which leaves 90. Need the differnce 90-10 = 80

Edit : and logitech beat me to it.
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Re: Tiles

by adilka » Mon Jan 12, 2009 7:45 pm
logitech wrote:And the difference = 80 ?
Correct, OA is 80.
adilka wrote:I made an uber-brainfart on this one!
I subtracted 10 from a 100, not 90 :lol:
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