Two cleaning companies, Spotless and As Good as New, offer house cleaning services. Spotless charges a flat fee of $30 and an additional $6 per hour while As Good as New charges $11 per hour with no flat fee. How long would cleaning a house have to take in order for the two companies to charge the same amount?

The ordering of the questions here is kind of confusing, so I'll just extract what seems to be relevant. They seem like True/False questions, but that's not clear to me.

There are no common elements between the sets A and C, so

A ∩ C = { } (the empty set)

Both sets A and B share the elements c and f, so

A ∩ B = {c, f }

and since we know A ∩ C is empty, we end up with

(A ∩ B) ∪ (A ∩ C) = {c, f } ∪ { } = {c, f }