$5.($For $15$ points$)$Christina Filtering Inc.$$ uses $12600($Yearly Demand$)$ air filters during the span of a year, and this

usage is relatively constant throughout the year. These air filters are bought from a supplier $30$ miles away for

$$30$ each, and it takes $8$ days from order to receipt. The carrying cost per unit per year is $20\%$ of the unit cost and

the ordering cost per order is $$65.$ There are $280$ working days per year.

a$.$ What is the Economic Order Quantity $($round to the nearest whole number$)?$

b$.$ What is the average inventory?

c$.$ About how many orders per year would be placed $($round to the nearest whole number$)?$

d$.$ What is the total Annual inventory cost $($Not just the total annual ordering and holding, but also including

purchased cost of air filter$)?$

e$.$ What is the Lead$-$time?

f$.$ What is the Re$-$ordering point? What does it mean in term of ordering filters?