A business buys invoice forms at a cost of $4.45 a box for the first 20 boxes, $4.00 a box for the next 25 boxes, and $3.75 a box for any additional boxes. How many boxes of invoice forms can be bought for $234.00?
Let X be the number of boxes of invoice forms that can be bought for $234.00.
The first 20 boxes cost 20 * $4.45 = $<<20*4.45=89.00>>89.00
The next 25 boxes cost 25 * $4.00 = $<<25*4=100.00>>100.00
The remaining X - 20 - 25 boxes cost (X - 20 - 25) * $3.75 = $<<3.75*(X-20-25)=3.75*(X-45)=3.75X-168.75>>3.75X - 168.75.
So, 89 + 100 + 3.75X - 168.75 = $234.00.
Therefore 3.75X = $234.00 + 168.75 - 89 - 100,
3.75X = $313.75,
X = $313.75 / 3.75 = <<313.75/3.75=83.33333333333333>>83.3333.
Since we can't buy a fraction of a box, the business can buy 83 boxes of invoice forms for $234.00. Answer: \boxed{83}.