11p4

解答

11 p 4

7920

求解步骤

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

代入

n = 11, r = 4

= \frac{11 !}{( 11 - 4 ) !}

\frac{11 !}{( 11 - 4 ) !} = 7920

= 7920

5 P 5

a r i t hm e t i c m e an 40, 40, 40, 46, 52, 52, 52

v a r ian ce 2, 3, 4, 5, 6

20 n C r 3

v a r ian ce 4, 6, 7, 9, 10, 11