Need help with these please

Compare profitability of products if joint costs are allocated under physical quantities, sales value at split-off, and NRV methods. Required (Round proportions to four decimal places, which is a percentage rounded to two decimal places.) specifying proportions under this method.) c. Allocate the joint costs under the NRV method and prepare (1) a partial income statement through gross margin and (2) the inventory section of the balance sheet. d. Compare the total amount of gross margin reported under all three methods. Why is it the same or different