Answer
$\frac{_{8}C_{4}}{_{12}C_{6}}=\frac{5}{66}\approx0.076$
Work Step by Step
$_{n}C_{r}=\frac{n!}{(n-r)!r!}$
$_{8}C_{4}=\frac{8!}{(8-4)!4!}=\frac{8\times7\times6\times5\times4!}{4!\times4!}=\frac{8\times7\times6\times5}{4\times3\times2\times1}=70$
$_{12}C_{6}=\frac{12!}{(12-6)!6!}=\frac{12\times11\times10\times9\times8\times7\times6!}{6!\times6!}=\frac{12\times11\times10\times9\times8\times7}{6\times5\times4\times3\times2\times1}=924$
$\frac{_{8}C_{4}}{_{12}C_{6}}=\frac{70}{924}=\frac{5}{66}\approx0.076$
