Kathleen bought 4 dresses that each cost the same amount and a pair of jeans that cost $40 the iteams she bought cost a total of $160 before tax was added.

The question seems incomplete, but if you are trying to figure out how much each dress costs, The answer would be $30.

To find the answer all you need to do is;
1. Subtract the price of the jeans ($40) From the total price.
160-40=120

2. Now we know the total price of the Dresses, and we also know she bought 4 of them, this means we can divide the total price ($120) of dresses, by the number (4) of dresses bought.
120/4 = 30.

So therefor, each dress costs $30 Dollars.

Hope this Helps! - Giz