10 choose 3

解答

10 c 3

120

求解步骤

= \frac{n !}{r ! ( n - r ) !}

代入

n = 10, r = 3

= \frac{10 !}{3 ! ( 10 - 3 ) !}

\frac{10 !}{3 ! ( 10 - 3 ) !} = 120

= 120

s t d 340, 75, 123, 259, 151

g eo m e t r i c m e an 8, 1

11 C 8

s t d 8, 16, 24, 65, 40

9 P 3