You decide to order a large two topping pizza. The pizza place has 10 toppings to choose from. You like to live on the edge, so you tell the person taking your order to surprise you with the two toppings. If the pizza maker picks the two toppings at random, what is the probability that you end up with pepperoni and sausage?

The answer is 1/100.

To calculate this, a multiplication rule is used. The multiplication rule calculates the probability that both of two events will occur. In this method, the possibilities of each event are multiplied.

There are in total 10 different toppings (1 of them is pepperoni and 1 of them is sausage) and we have 2 events occurring together:

1. the probability (P1) that you end up with pepperoni: P1 = 1/10

2. the probability (P2) that you end up with sausage: P2 = 1/10

Now, using the multiplication rule, the probability (P) that you end up with pepperoni and sausage is 1/100:

P = P1 · P2 = 1/10 · 1/10 = 1/100