The correct answer is 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 29
because we want to count all the different ways, we can choose some subset of n things, we get the answer 2n
A common incorrect answer would be
. It is the number of ways we could permute the 9 toppings on burger like "first lettuce, then tomato, then mustard, then pickle”, etc., would be one permutation and a different permutation would be "first tomato, then lettuce, then mustard, then pickle etc.