Tom paid a 15 percent salea tax on a discount he paid 90 in a sale tax how much did he pay altogether for the suitcase
Let's represent the original price of the suitcase as 'x'.
If Tom paid a 15% sales tax, he paid 15/100 * x = 0.15x in sales tax.
Since he paid a discount, he paid 0.85x for the suitcase.
We are told that the sales tax was $90, so 0.15x = 90.
Dividing both sides by 0.15, we find x = 90 / 0.15 = $600.
Therefore, Tom paid 0.85x = 0.85 * 600 = $<<0.85*600=510>>510 altogether for the suitcase. Answer: \boxed{510}.