please answer asap I only have 30 minutes

Tober Inc, operates a lumber yard. Tober incurs joint costs of $85,000 to obtain three observable joint products. Further processing and finat sales values for the products are as follows: What is the gross margin for the 30ft board using the net realizable value (NRV) method to allocate joint costs? (Round to the nearest whole dollar.) $43,000 $14,220 $28.780 $55,000