推 maoc: 超幾何? 10/26 21:34
→ celestialgod: 1. let X=number of drawing to find fake gold br 10/26 22:54
→ celestialgod: ick, then P(X>=3)=1-P(X=1)-P(X=2) 10/26 22:54
→ celestialgod: =1-1/10-9/10*1/9=4/5 10/26 22:55
→ celestialgod: 2. 9C2*1C1/10C3=9*8/2/(10*9*8/3/2)=0.3 10/26 22:56
推 rebe212296: 有放回不會是超幾何 10/27 02:02