Question

compute : 7c4

Answer 1

\[\large \color{green}{^nC_r = \frac{n!}{(n-r)! \times r!}}\]

\[\large ^7C_4 = \frac{71}{(7-4)! \times 4!} \implies \frac{7 \times 6 \times 5 \times 4!}{4! \times 3!}\]

\[\implies\frac{7 \times 6 \times 5}{3 \times 2} \implies 7 \times 5 = ??\]