you have two assets land and the building. both were sold.
thus, the sales price and the selling costs must be allocated between the land and building
in Turbotax this can be done by showing total cost of $280K and then entering the land value on the same worksheet as $40K. Turbotax will use a depreciable basis for the building as $240k. you then would enter the allocated amounts for each item on the worksheet
one way is based on their original cost, but the proper way is based on their relative fair market value
so combined
sales price 320,000
cost building 240,000
land 40,000
expenses 16,891
depreciation (16,000)
net 280,891
gain 39.019
