I,m only starting to use equations

I,m looking to distrbute holes or parts at a specified distance with the quantity of each increasing or decreasing as the part is varied in size. I also want to incorporate a minimum and maximum edge disdantce. This might require the items to be either symmetrical across the centre or one on the centre to satisfy the edge distance.

For example say a flat extrusion 100(distance 1) x20mm has a series of holes along it with the minimum edge distance 5mm and the max edge distance 10mm to the edge of the holes. The 2 end holes will always be the same distance from the ends but as distance 1 increases/decreases the number of items may change as may the the fact that there will either be a centrally or symetrically placed hole(s) dependant on the distance 1.

Regards

Phil