Answer:
The journal entry to record wages and salaries on Friday should be:
Friday, January 2, wages and salaries:
Dr Wages and salaries expenses 7,200
Dr Salaries payable 4,800
Cr Cash 12,000
Wages and salaries expenses includes the wages corresponding to December 29-31 (3 days) = ($12,000 / 5 days) x 3 days = $7,200