Question $1(4+5+6=15$ points$)$ EOQ model

Universal Bikes is a manufacturing company that uses gear assemblies to produce four different

models of mountain bikes. One of these gear assemblies, the "Smooth Shifter," is used for the

two most expensive models, and has an estimated annual demand of $900$ units. The Universal

Bikes estimates the cost to place an order is $$100,$ and the holding cost for each assembly is $$200$

per year.