process costing system(FIFO)

given opening work in progress 200units with a total value of $1530.input to the process 1000 unit ,completed production 1040 unit.
last month the cost per equivalent unit of production was $20 and the degree of the completion of the work in progress was 40% throughout the month .

what was the value at (cost)of last month’s closing work in progress? answer= $1280

what was the cost of the 1040 units completed last month? answer =$20730

to calculate the closing work in progress is it ,1040+200-1000
i have no idea how to proceed after that