Chapter 12 - Counting and Probability - Section 12.2 Permutations and Combinations - 12.2 Assess Your Understanding: 17

$C(7,4) = 35$

Work Step by Step

Use the formula $C(n, r)=\dfrac{n!}{(n-r)!r!}$: $C(7,4) \\= \dfrac{7!}{(7-4)!4!} \\= \dfrac{7!}{3!\times4!} \\=\dfrac{7\times6\times5\times4!}{3!\times4!} \\= \dfrac{7\times6\times5}{3\times2\times1} \\= \dfrac{210}{6} \\= 35$

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.