how to calculate if one cell amount differ & other cell amount fixed

Hellow friends

Using excel 2003
I required if in particular cell amount is differ & other cell amount fixed. Then how to calculate in another cell. The data are as given below :

If in column T2=1 then calculate 10% on total amount.
If in column T2=2 then calculate 20% on total amount.
If in column T2=3 then calculate 30% on total amount.
If in column T2=4 then calculate 40% on total amount.

Total amount in column X2 suppose : 100.00

I required formula in column Y
If in column T2=1 then calculate 10% on total amount 100.00 : - Result will be show as 90.00
If in column T2=2 then calculate 20% on total amount 100.00 : - Result will be show as 80.00
If in column T2=3 then calculate 30% on total amount 100.00 : - Result will be show as 70.00
If in column T2=4 then calculate 40% on total amount 100.00 : - Result will be show as 60.00

Perhaps simply:

Y2: =X2*(1-10%*T2)