1. The problem asks to evaluate the combination expression $15C4$, which represents the number of ways to choose 4 items from 15 without regard to order.
2. The formula for combinations is:
$$nCr = \frac{n!}{r!(n-r)!}$$
where $n$ is the total number of items, and $r$ is the number of items chosen.
3. Substitute $n=15$ and $r=4$:
$$15C4 = \frac{15!}{4!(15-4)!} = \frac{15!}{4!11!}$$
4. Simplify the factorial expression by expanding only the necessary terms:
$$15C4 = \frac{15 \times 14 \times 13 \times 12 \times \cancel{11!}}{4! \times \cancel{11!}} = \frac{15 \times 14 \times 13 \times 12}{4!}$$
5. Calculate the numerator:
$$15 \times 14 = 210$$
$$210 \times 13 = 2730$$
$$2730 \times 12 = 32760$$
6. Calculate the denominator:
$$4! = 4 \times 3 \times 2 \times 1 = 24$$
7. Divide numerator by denominator:
$$15C4 = \frac{32760}{24}$$
8. Simplify the fraction by canceling common factors:
$$\frac{\cancel{32760}^{1365}}{\cancel{24}^{1}} = 1365$$
9. Since the result is an integer, the value of $15C4$ is 1365.
Final answer:
$$15C4 = 1365$$
Combination 15C4 85Acec
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