Accounting For Labor

Dear John,

For the below question the Marking Scheme illustrates the Answer as: (4,800 units × 5 hours × $10 per hour) ÷ 0.80 =$300,000

I don’t seem to understand the part how & why we divide by ÷ 0.80

Please be kind enough to explain.

Question;
Budgeted production in a factory for next period is 4,800 units.
Each unit
requires five labour hours to make. Labour is paid $10 per hour.
Idle time
represents 20% of the total labour time.

What is the budgeted total labour cost for the
next period?

Thank You!