The key thing to look at is that the period ends on FRIDAY.
If we count from Monday to Friday, that is 5 days apart.
We need to divide to find the daily salary.
18,000 / 6 = $3,000 per day
Multiply to find the total salary expense from Monday to Friday.
3,000 * 5 = $15,000
Now, we can assemble the journal entry.
We will have a salaries expense to debit for $15,000
We will also have a salaries payable to credit for $15,000
18,000 - 15,000 = $3,000 expense for the next accounting period.
Best of Luck!