Answer:
286
Step-by-step explanation:
Since we are looking for the number of combination, we use the formula:
[tex]_{n}C_{r}=\dfrac{n!}{(n-r)!r!}[/tex]
n = 13
r = 3
[tex]_{13}C_{3}=\dfrac{13!}{(13-3)!3!}[/tex]
[tex]_{13}C_{3}=\dfrac{13!}{10!3!}[/tex]
[tex]_{13}C_{3}=286[/tex]
So there are 286 possible combinations of 13 toppings at 3 toppings on a large sundae.