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ææçåºé¢ç§æ°ä¸º C6 4 4é¢å
¨å¯¹æ¶ä¸º C4 4 ç对ä¸é¢æ¶ä¸ºC4 3 * C2 1
æ¦ç为 (C4 3 * C2 1)+C4 4 / C6 4 =3/5
è³å°æä¸äººæåæ¦ç为P=1 - ï¼1-2/3ï¼*ï¼1-3/5ï¼=13/15
2 å½æå人æ°ä¸º 0 æ¶
é½ä¸æå P=ï¼1-2/3ï¼*(1-2/3ï¼*ï¼1-3/5ï¼*ï¼1-3/5ï¼=4/225
å½æå人æ°ä¸º 1 æ¶
ç²ä¹ä¸äººæåæä¸ä¸ä¸äººæå
p=C2 1 * 2/3 *ï¼1-2/3ï¼*ï¼1-3/5ï¼*ï¼1-3/5) +ï¼1-2/3ï¼*ï¼1-2/3ï¼* C2 1 * 3/5 *ï¼1-3/5)=28/225
å½æå人æ°ä¸º 2æ¶
ç²ä¹æå æä¸ä¸æå æ ç²ä¹ ä¸ä¸åæä¸äººæå
p= 2/3 *2/3*ï¼1-3/5ï¼*ï¼1-3/5) +C2 1 * 2/3 *ï¼1-2/3ï¼* C2 1 * 3/5 *ï¼1-3/5)+
ï¼1-2/3ï¼*ï¼1-2/3ï¼ * 3/5 * 3/5=73/225
å½æå人æ°ä¸º 3æ¶
ç²ä¹ä¸äººä¸æåæ ä¸ä¸ä¸äººä¸æå
p= C2 1 * 2/3 *ï¼1-2/3ï¼* 3/5 * 3/5 + 2/3 * 2/3 * C2 1 * 3/5 *ï¼1-3/5)=84/225
å½æå人æ°ä¸º 4æ¶
ç²ä¹ä¸ä¸é½æå
p= 2/3 *2/3* 3/5 * 3/5 =36/225
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