Question

Хотя бы одна задача.

Answer 1

$2)\; \; \; P=\frac{C_{16}^6}{C_{20}^6}=\frac{16\cdot 15\cdot 14\cdot 13\cdot 12\cdot 11}{20\cdot 19\cdot 18\cdot 17\cdot 16\cdot 15}=\frac{14\cdot 13\cdot 12\cdot 11}{20\cdot 19\cdot 18\cdot 17}=\frac{1001}{4845}\approx 0,2066\\\\\\3)\; \; P=1-\frac{C_{20}^3}{C_{30}^3}=1-\frac{20\cdot 19\cdot 18}{30\cdot 29\cdot 28}=1-\frac{342}{1218}=1-\frac{57}{203}=\frac{146}{203} \approx 0,7192$