Problem: a university cafeteria offers 6 flavors of pizza - pork , gobi - manjurian , pepperoni , chicken , hawaiian and vegetarian . if a customer has an option ( but not the obligation ) to add extra cheese , mushrooms or both to any kind of pizza , how many different pizza varieties are available ?
Rationale: 6 flavours * 6 choices = 6 c 1 * 6 c 1 = 6 * 6 = 36 = d
annotated_formula: multiply(6, 6)