This is a worksheet where I have a dollar amount that I would enter into a
cell that I want to achieve. (An annual return on my investment.) cell:
(N9)

I have:
1) A cell listing the initial cost of the investment per unit. cell:
(E11)
2) A cell listing the annual return on the investment per unit purchased.
cell: (F11)
3) A cell listing the current cost of the investment per unit. cell: (H11)
--This cell has a formula in it.
=IF(E110,((E11)*(1+(G11*0.1))),"N/A")
4) A cell listing the number of units I currently own. cell: (G11)
5) A cell listing the number of units I need to buy to achieve the value in
cell "N9".
--This cell has a formula in it.
=IF(F110,ROUNDUP(($N$9/F11),0),"N/A")
6) I would like to enter a formula into cell "M11" that returns the total
cost of my investment to receive the return I entered into cell "N9".

Here is my problem:
1) The cost of the investment increases by 10% per total units purchased
each time a purchase is completed.
2) The maximum number of units that can be purchased in each transaction is
ten.
(All ten units would be purchased at the current unit cost "H11"
then the current cost "H11" would increase.)

EX: Current Cost = $200. I buy 1 unit new Current Cost = $220, I then buy
10 more units at $220 each. This costs me $2,200 and the new Current Cost =
$420.

If I now want to buy 23 more units to achieve the new additional return on
my investment requirement I would have to buy 10 units at $420 (cost $4,200)
and 10 units at $620 (cost $6,200) and then 3 units at $820 (cost $2,460).

Total Cost = $12,860 (The value I want to be returned in cell"M11".)

The new Current Cost would now be $880 for any future purchases.

--Also the number of units being purchased could easily be well over 1,000
units.


Can anyone help me out with this?

Thank You, very much!