Given:
Number of choices offered, n = 15
Number of toppings (sample), r = 4
Let's find the number of possible 4-topping pizzas possible.
To solve this exercise, we are to use combination.
Combination involves the arrangement of objects without any repitition of orders of arrangement.
Apply the formula:
[tex]^nC_r=\frac{n!}{r!(n-r)!}[/tex]Thus, we have:
[tex]^{15}C_4=\frac{15!}{4!(15-4)!}[/tex]Solving further:
[tex]\begin{gathered} ^{15}C_4=\frac{15!}{4!(11)!} \\ \\ ^{15}C_4=\frac{15\ast14\ast13\ast12\ast11!}{4\ast3\ast2\ast1\ast11!} \\ \\ ^{15}C_4=\frac{15\ast14\ast13\ast12}{4\ast3\ast2\ast1} \\ \\ ^{15}C_4=\frac{32760}{24} \\ \\ ^{15}C_4=1365 \end{gathered}[/tex]Therefore, there are 1365 possible 4-topping pizzas.
ANSWER:
1365