What is the formula to calculate the total percentage of provision, provided that each object has its own percentage of provision?

Question

Electronic accounting

Problem example:
We know only data on % security and nothing more. It is necessary to calculate (accept) % of the provision of the parent organization, % of the provision of the parent organization is the sum of the provision of branches
Conditions:
Head organization
Provision percentage - ?
Branch No. 1
Percentage of provision with equipment - 20%
Branch No. 2
Percentage of provision with equipment - 100%
So,
the Parent Organization
Percentage of provision - ???
We cannot write that the % security of the Head Organization is 100%. % security of branch No. 1 is only 20, and we cannot write 20%, because % security of branch No. 2 100%.
What is the percentage of the head organization's security, if it is made up of the security of the branches? Is it possible to somehow calculate this, knowing only the percentage data?

Answer 1

Sorry, all the same, I kind of decided:
The sum of the values ​​​​of the "Percentage of provision with equipment" field for each of the branches / (Number of branches * 100) * 100