Answer: 64
Explanation:
You can write the equation to solve this problem very easily by doing a rule of three:
9/16 --------- 36
16/16--------- x
This can be read as: if 36 people represent 9/16 of the volunteers at the shelter, then how many people (x) represent the total (16/16) of the volunteers at the shelter.
By solving the rule of three, you get the equation:

And then you solve:

So the total of the volunteers that help at the local shelter is 64.