9514 1404 393
Answer:
120
Explanation:
We assume the order of the toppings does not matter. Then the number of interest is the number of combinations of 10 toppings taken 3 at a time. That is given by ...
10C3 = C(10, 3) = 10!/(3!(10 -3)!) = 10·9·8/(3·2·1) = 120
120 different 3-topping pizzas can be made if 10 toppings are available.
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Additional comment
If order matters, then 10 choices can be made for the first topping, 9 for the second, and 8 for the third, for a total of 10×9×8 = 720 different pizzas.