GMATprep2: Isaac can purchase a certain item in four d

[nhai2003]

1) Internet: $80, with no sales tax, plus $10 shipping fee
2) Store X: $90, a 10% discount, plus 10% tax on discounted price
3) Store Y: $90, no tax
4) Store Z: $90, a 10% sales tax, and $10 rebate after tax

Isaac can purchase a certain item in four different ways, as shown in the table. What is the lowest price for which he can purchase this item?
- 88.10
- 89.00
- 89.10
- 89.50
- 90.00

I thought it is 89.10
[spoiler]OA: 89.00[/spoiler]

[mike22629]

Just work the problem out....

Statement 4)

First 10% tax
90 + .1*90 = 99

Then $10 rebate
99-10 = 89