At a certain pizzeria, it is known that 12% of orders are for extra-large pizzas. What is the expected number of pizzas that will be ordered until the first extra-large pizza is ordered?

The number of orders until the first extra-large pizza follows a geometric distribution with success probability 0.12. Its expected waiting time, counting the successful order, is 1 ÷ 0.12 = 8.33 orders. Therefore, the expected number is 8.33 pizzas, choice C.

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