A1 = Monthly Inventory Value of 12
A2 = Monthly Cost of Goods Sold of 3
A3 = =A1*12/A2 [this give me the turn rate of: 3

To calculate the weeks supply of product I would use the following formula:
=A1/SUM(SUM(A2*12)/52) [this gives me 17.333 weeks supply]

It would be helpful to have a calculation that could arrive at the weeks
supply without having to have access to both the Inventory Value or the Cost
of Goods Sold.

Is it possible to calculate the Weeks supply with only the turn rate and one
of the other two? In other words if all you had was the turn rate and the
inventory or just the turn rate and the cost of goods sold, could you come up
with the weeks supply?