A pizza chain offers cheese pizzas with a choice of these toppings:
pepperoni, onion, sausage, mushrooms, and anchovies.
a) Explain why the pizza chain can claim to offer 32 different pizzas.
b) Another pizza chain claims that with its choice of toppings, it can
create just over 1000 pizzas. What is the minimum number of
toppings it must offer?