yup those are problems, I'm going to unpublish it in the meantime and address these flaws

Hi, thank you for beta testing. The grid seems to be confusing everybody including me. According to my system zone 25 would return all sales in coordinates [40.20,40.29] [-90.60,-90.51]

row 1 [40.00, 40.09] zone(1,10)
row 2 [40.10, 40.19] zone(11,20)
row 3 [40.20, 40.29] zone(21,30)
  
column 1 [-91.00,-90.91] zones 1,11,21 etc..
column 2 [-90.90,-90.81] zones 2,12,22, etc..
column 3 [-90.80,-90.71]  
column 4 [-90.70,-90.61]  
column 5 [-90.60,-90.51] zones 5,15,25 etc...

perhaps I could make it clearer by including a diagram?

thanks for the tips

Good point, that is a problem. Perhaps it would make more sense if the data I provided only went to the 2nd decimal place?
I was not familiar with [) I'll edit the description to use that
I considered having it so that the max and min longitude and latitude would be different every time as well as the range between them which would leave it up to the solver to determine the boundries of each grid square. I think that would make the problem more involved than it really needs to be though.

My sample test cases were wrong. They applied to an older version of the data which I replaced. I also changed the lat, lon description so it is hopefully more clear now.
zone 91 would be lat 41.90,41.99 lon -91.00,-90.91, when you hit lon -90.90 you are in the second column of the grid. The Kata is live again now and If you want to give it a try!

hi, thanks for giving it a try
I think I might have mixed up latitude and longitude somewhere in the solution or test. Zone 91 should be the 10th row from bottom and first square in the row.
I may have a problem with my solution or test, will check tomorrow and unpublish in the meantime.
First time posting a Kata for me

I enjoyed this Kata. I thought it was more interesting than most. I actually found it somewhat difficult for a 6. There are 4kyus that I've been able to solve more quickly than this. Anyone else think so?