Hi shasadou,
This question can be solved in a variety of ways: with algebra, by TESTing THE ANSWERS and by using a great Number Property shortcut involving consecutive integers.
We're given a few facts to work with:
1) There are 9 rows of tiles.
2) When going from 'left to right', each row contains TWO FEWER tiles than the one next to it.
3) There are a total of 504 tiles
We're asked how many tiles the left-most most row holds (meaning the one with the MOST tiles).
To start, 504 is divisible by 9, so we can figure out the AVERAGE number of tiles per row. That is 504/9 = 56. Since we're dealing with a set of 9 consecutive integers that differ by 2 each, we know that the '5th row' will have 56 tiles (the average). Then we just have to 'add 2s' until we get to the first row...
56 +2 +2 +2 +2 = 64.
Final Answer:
GMAT assassins aren't born, they're made,
Rich
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