Total Annual Cost – Holding cost question

Here’s the question:

‘each unit is bought in at a cost of $2.24 from supplier…..

The total holding cost is 10% per annum of the value of inventory held.’

How do you find the total holding cost?
(i.e. what is the value of inventory held?)

I know you use Ch×Q/2 to find total holding cost. just not sure why value of inventory is related to the purchase cost of each unit.

Kind regards,
Hwan