And/or just means that either "and" or "or" may be used in the sentence. In pure logic, OR means and/or, and XOR (exclusive or) means or. Observe:
A AND B : Both A and B must exist A OR B : A must exist, or B must exist, or both A and B must exist A XOR B : A must exist, or B must exist, but NOT BOTH A and B
If I was inviting two people to a barbecue, I could