The problem states:

The weekly demand for propane gas (in 1000s of gallons) from a particular facility is an rv *X* with pdf

If 1.5 gallons are in stock at the beginning of the week and no new supply is due in during the week, how much of the 1.5 thousand gallons is expected to be left at the end of the week? [hint: let h(x)=amount left when demand =x.]

As far as I understand, to solve the problem I need to calculate:

And E(h(X)) would be the answer for the problem. But what is the h(x)??? Is it (1.5-x) or is it something else?