
Town Hall Tiles
http://i209.photobucket.com/albums/b...ATHDIAGRAM.jpg
The diagram above (sorry my diagram isnt too great..) contains black and white tiles in a diamond formation. There are 7 tiles across and 25 tiles in total. Now I need to find how many tiles there would be in total, if the number of tiles across was 149. The formula I am using is n+x^2/y
So for the 7 across, the formula would be 7+x^2/y = 25
The only problem is, I cant work out what x and y are.
If you could help me finding what x and y are, that would be greatly appreciated.
Holly.


In case this helps, Aidan's formula "comes from" the formula:
sum of 1st n odd numbers = n^2; like 1 + 3 + 5 = 3^2
In your example, this occurs twice (above and below the middle row),
hence 2(1 + 3 + 5) + 7 = 25