Joe goes to a mexican resturant and orders nachos. he can have just cheese or any of the following: chicken, onions, sour cream, or olives. how many different variations of nachos are possible

Since there is no specific order at which he can select the ingredient, in this case we shall use the combinations to compute for the variation of nachos Joe can have. This will be given by:
5C1
=5
We therefore conclude that Joe will have 5 variations

Ithink the answer would be knew