Answer:
7,071 gears
Step-by-step explanation:
As the cost of inventory has not been provided, hence I assumed the cost of one unit of Inventory is $20
The Economic order quantity will minimize the total costs
Use the following formula to calculate the Economic Order Quantity
Economic Order Quantity =

Where
D = Demand = 100,000 gears
S = Cost per order = $1,000
H = Carrying cost per gear = $20 x 20% = $4
Placing values in the formula
Economic Order Quantity =

Economic Order Quantity = 7,071 gears