Need a formula to come up with total cost.. need help with the Labor Usage % portion

I can't figure out how to incorporate the Labor Usage (%) in my formula

I need an excel formula for the following:

Order Quantity
Production Time (Hours)
Labor Usage (%).......................The percentage of the production time that workers are paid at the specified labor rate
Labor Rate ($/HR)
Number of Workers

to get Total Cost
to get Cost Per Part

example

Order Quantity is 120
Production Time (Hours) 5
Labor Usage (%) 85%
Labor Rate ($/HR) $8.00
Number of Workers 6

Answer is
Total cost $204.00
Cost Per Part $ 1.70

Total Cost = Production Time × Labor Usage (%) × Labor Rate ($/HR) × Number of Workers
Cost per Part = Total Cost ÷ Order Quantity

The problem I see with your method is there is no accounting for materials and overhead... unless all you are after is labor cost.

Yes just looking for labor costs..