Why are cashmere sweaters usually not sold in discount stores?


Customers who buy cashmere sweaters typically have inelastic demand,
Cashmere costs too much for discount retailers to buy, the markup for cashmere sweaters is often very high or all of the above?

I am stumped on my accounting questions. There are many steps on computing the NPV, I have computed the net income and expese amount, but how do I compute the npv of income?