Answer:
Necessarily it could be anything
Step-by-step explanation:
If you want a repeating decimal digit of 0 it's going to be all decimals just to a different place like the tenths place. For example 0.5 is also 0.500000000000... That is why pretty much every decimal has a repeating digit of 0.
1. Intersection
2. complement
3. Union
4. finite set
5. disjoint sets
6. proper subset
7. subset
If they sold 89 calendars over 4 weeks, the 'equation' would look like (x = average calendars sold over 4 weeks):

If you solve it, you get:

Which is equal to
22.25. Hope this helps!