I am not following the logic of your calculation (not really sure what you are doing there, or trying to show us).
If something costs 1500, and then you apply a 10% discount to that, the final cost would be 1350.
The calculation is simply:
= initial value * (1 - discount percent)
If 1500 is the discounted price, and you know there was a 10% discount, then the original price would be 1667.67.
The calculation is simply:
= initial value / (1 - discount percent)
They are two entirely different calculations (they go in opposite directions).
In the first one, 1500 is the cost BEFORE discount (so you are trying to figure out the discounted price).
In the second one, 1500 is the cost AFTER discount (so you are trying to figure out the original prices)