在一个口袋中，装有质地、大小均相同、颜色不同的红球3个，蓝球4个，黄球5个，现在随机抽取一个球是红球 口袋中有大小、质地均相同的7个球，3个红球，4个黑球，现在从...
\u5728\u4e00\u4e2a\u53e3\u888b\u4e2d\uff0c\u88c5\u6709\u8d28\u5730\u3001\u5927\u5c0f\u5747\u76f8\u540c\u3001\u989c\u8272\u4e0d\u540c\u7684\u7ea2\u74033\u4e2a\uff0c\u84dd\u74034\u4e2a\uff0c\u9ec4\u74035\u4e2a\uff0c\u73b0\u5728\u968f\u673a\u62bd\u53d6\u4e00\u4e2a\u7403\u662f\u7ea2\u7403C\uff0e \u8bd5\u9898\u5206\u6790\uff1a\u6839\u636e\u6982\u7387\u7684\u6c42\u6cd5\uff0c\u627e\u51c6\u4e24\u70b9\uff1a\u2460\u5168\u90e8\u7b49\u53ef\u80fd\u60c5\u51b5\u7684\u603b\u6570\uff1b\u2461\u7b26\u5408\u6761\u4ef6\u7684\u60c5\u51b5\u6570\u76ee\uff1b\u4e8c\u8005\u7684\u6bd4\u503c\u5c31\u662f\u5176\u53d1\u751f\u7684\u6982\u7387. \u56e0\u6b64\uff0c\u2235\u5730\u53e3\u888b\u4e2d\u5171\u67093+4+5=12\u4e2a\u7403\uff0c\u5176\u4e2d\u7ea2\u74033\u4e2a\uff0c\u2234\u968f\u673a\u62bd\u53d6\u4e00\u4e2a\u7403\u662f\u7ea2\u7403\u7684\u6982\u7387\u662f .\u6545\u9009C\uff0e
\uff081\uff09\u8bbe\u201c\u53d6\u51fa\u7684\u7403\u989c\u8272\u76f8\u540c\u201d\u4e3a\u4e8b\u4ef6A\uff0cP(A)\uff1dC33C37+C34C37\uff1d535\uff1d17\uff0c\u6240\u4ee5\u53d6\u51fa\u7684\u7403\u989c\u8272\u76f8\u540c\u7684\u6982\u7387\u4e3a17\uff0e\u2026\uff084\u5206\uff09\uff082\uff09\u03be\u7684\u53ef\u80fd\u53d6\u503c\u4e3a0\uff0c1\uff0c2\uff0c3\uff0cP(\u03be\uff1d0)\uff1dC03C34C37\uff1d435\uff0cP(\u03be\uff1d1)\uff1dC13C24C37\uff1d1835\uff0cP(\u03be\uff1d2)\uff1dC23C14C37\uff1d1235\uff0cP(\u03be\uff1d3)\uff1dC33C04C37\uff1d135\uff0c\u2026\uff088\u5206\uff09\u03be\u7684\u5206\u5e03\u5217\u4e3a\uff1a\u03be0123P43518351235135\u2026\uff0810\u5206\uff09\u2234E\u03be\uff1d0\u00d7435+1\u00d71835+2\u00d71235+3\u00d7135\uff1d4535\uff1d97\uff0e\u2026\uff0812\u5206\uff09
∵一个袋中装有红球3个，蓝球4个，黄球5个共有12个小球，红球有3个，∴从袋中随机摸出一个球，摸到红球的概率是：
| 3 |
| 12 |
| 1 |
| 4 |
故选；C．
绛旓細鏍规嵁棰樻剰锛屽彛琚嬩腑鏈6涓悆锛屽叾涓3涓孩鐞冦2涓粍鐞冨拰1涓鐧界悆锛 鍒欑孩鐞冨拰鐧界悆鍏辨湁4涓紝 鏁呬粠涓殢鏈烘懜鍑1涓悆锛岄偅涔堟懜鍒扮孩鐞冩垨鐧界悆鐨勬鐜囨槸 4 6 = 2 3 锛 鏁呴塂锛
绛旓細鎽稿埌绾㈢悆鐨勫绔嬩簨浠舵槸鈥滄懜鍒扮殑閮芥槸鐧界悆鈥漃锛堟懜鍒伴兘鏄櫧鐞冿級锛1/6 鎵浠ワ紝鎽稿埌绾㈢悆鐨勬鐜囨槸1-1/6=5/6
绛旓細1 5+4+3/8*7*6=1/28 2 5+4+3/8*7*6=1/28 3 5/8 4 3+5+2/8*7*6=5/168
绛旓細4 渚濋鎰忓緱锛屛剧殑鍙兘鍙栧煎垎鍒槸0,1,2,3,4,5,6锛屼笖姣忔鍙栫悆鍙栧嚭绾㈢悆鐨勬鐜囧潎鏄 锛 锛屾晠尉锝濨(6锛 )锛屽洜姝(尉)锛6脳 锛4.
绛旓細鐢绘爲鐘跺浘寰楋細鈭靛叡鏈9绉嶇瓑鍙兘鐨勭粨鏋滐紝涓ゆ鎽稿嚭鐨勫皬鐞冮鑹茬浉鍚岀殑鏈3绉嶆儏鍐碉紝鈭翠袱娆℃懜鍑虹殑灏忕悆棰滆壊鐩稿悓鐨勬鐜囨槸锛39=13锛庢晠绛旀涓猴細13锛
绛旓細锛1锛夊埄鐢ㄥ浘琛ㄥ緱鍑猴細瀹為獙娆℃暟瓒婂ぇ瓒婃帴杩戝疄闄呮鐜囷紝鎵浠ュ嚭鐜扳滃拰涓8鈥濈殑姒傜巼鏄0.33锛庯紙2锛夌瓟锛氫笉鍙互鍙7锛庘埖褰搙=7鏃讹紝锛堜篃鍙互鐢绘爲鐘跺浘锛夆埓涓や釜灏忕悆涓婃暟瀛椾箣鍜屼负9鐨勬鐜囨槸锛212=16鈮13锛屽綋x=5鏃讹紝涓や釜灏忕悆涓婃暟瀛椾箣鍜屼负9鐨勬鐜囨槸13锛庯紙绛旀涓嶅敮涓锛屼篃鍙互鏄4銆6锛夛紟
绛旓細瑙ｏ細(1) 鍑虹幇鍜屼负7鐨勬鐜囨槸锛0.33(鎴0.31锛 0.32锛0.34鍧囨纭)(2) 鍒楄〃鏍硷紙瑙佷笅杈癸級鎴栨爲鐘跺浘锛屼竴鍏辨湁12绉嶅彲鑳界殑缁撴灉,鐢憋紙1锛夌煡锛屽嚭鐜板拰涓7鐨勬鐜囩害涓0.33 鈭村拰涓7鍑虹幇鐨勬鏁颁负0.33脳12=3.96鈮4(鐢ㄥ彟澶栦笁涓鐜囦及璁″艰鏄庝害鍙)鑻2+x=7,鍒檟=5,姝ゆ椂P锛堝拰涓7锛=鈮0.33, ...
绛旓細4涓悆姣忔鎽稿嚭2涓潵锛屼竴鍏辨湁C(4,2)绉嶇粍鍚堬紝鑰岀瓑浜8鐨勭粍鍚堝彧鏈3/5鍜5/3锛2绉嶏紝鎵浠ュ拰涓8鐨勭粍鍚堝嚭鐜扮殑姒傜巼涓2/C(4,2)=2/6=1/3銆傛墍浠ユ鐜囦负0.3333333...
绛旓細涓嶆槸鍚屼竴浠朵簨銆傞兘涓嶇浉鍚岋紝鏄庢樉鏄瑕佹眰鎽稿嚭鐨勬槸涓涓孩鐞锛屼竴涓榛勭悆鍜屼竴涓摑鐞冦傝屼笉閮界浉鍚岋紝鍒欏彲浠ユ槸涓ら粍涓绾紝涓よ摑涓榛勬垨涓ら粍涓钃濓紝鍖呮嫭涓夎呴鑹插悇涓嶇浉鍚屻傛讳箣鍙涓嶆槸涓夎摑锛岄兘鎴愮珛銆傚彲浠ョ湅鍑哄悗鑰呮鐜囨瘮鍓嶈呰澶э紝浜岃呬笉鏄悓涓浜嬩欢銆
绛旓細瑙ｏ細锛1锛夊鍥撅細 鈭磋兘缁勬垚鐨勪袱浣嶆暟鏈21锛31锛12锛32锛13锛23锛 鑳界粍鎴愮殑涓や綅鏁版湁21锛31锛12锛32锛13锛23锛涳紙2锛 銆
