The following information has been extracted from the trial balance of Tile Africa CC$,$ a manufacturer with a reporting date of $31$ December $2020$:

N$ Dr$/($Cr$)$

Sales

$(800,000)$

Finished goods $-1$ Jan $2020$

$80,000$

Work in progress $-1$ Jan $2020$

$60,000$

Raw materials $-1$ Jan $2020$

$70,000$

Purchases of raw materials

$150,000$

Variable production cost

$120,000$

Fixed production overheads

$100,000$

Additional information

During the year there was an abnormal spillage of raw materials of N$$20,000.$

Fixed production overheads are allocated at N$$2$ per unit based on normal capacity of $50,000$ units. The actual production for $2020$ was $40,000$ units.

Closing inventory is as follows Raw materials N$$70,000,$ Work in progress N$$90,000$ and Finished goods N$$40,000.$

N$$270,000$ work in progress were transferred to finished goods

Required

Calculate the cost of sales expense