How to calculate weight based cost?

I have a very simple pricing structure, but i have been trying a bunch of combo but still cannot get the price correct.

I just want to increase the price to multiply according to the weight since each product is weight at 1.

So each product weight is 1 KG, using this formula below, but can’t get the pricing to go up when i increase the quantity.

0 > 1 = $1
1 > 2 = $2

According to this logic, it should go up to $2 when i have 2 products in cart.