J+W 寫到:(1)“假定有5%的人口濫用一種禁藥﹐而這種藥的檢驗準確度是95%。某人的檢驗結果是陽性﹐他確曾使用這種禁藥的可能性多大﹖”
#ed_op#DIV#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#多謝指教#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#是我弄錯題意了#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#其實之前建議時忘了還有一項條件,就是#ed_op#FONT color=#0000ff#ed_cl#兩項工作第一年的薪水都是一萬元#ed_op#/FONT#ed_cl#,爾後一項是年薪一萬每年加薪一千,另一項是半年薪五千每半年加薪三百。乍看之下好像是前者優於後者,但仔細推算,長久下來竟是後者優於前者。#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl#
#ed_op#DIV#ed_cl#請看清楚題目:SKYMEN 寫到:就題目給的條件一個第一年領11000元,每年增加1000元;一個第一年領10600元,之後每年增加600元,怎麼算都是前者划算啊,後者只會越差越多。yunhan 寫到:#ed_op#SPAN#ed_cl##ed_op#SPAN class=postbody#ed_cl##ed_op#FONT size=2#ed_cl#(9)半年薪,約在4年底就可以超過一年薪#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl#
#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#其實之前建議時忘了還有一項條件,就是#ed_op#FONT color=#0000ff#ed_cl#兩項工作第一年的薪水都是一萬元#ed_op#/FONT#ed_cl#,爾後一項是年薪一萬每年加薪一千,另一項是半年薪五千每半年加薪三百。乍看之下好像是前者優於後者,但仔細推算,長久下來竟是後者優於前者。#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#推算如下:#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#A工作(年薪10000,每年加薪1000):#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#第一年:10000#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#第二年:10000+1000=11000 共得10000+11000=21000#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#第三年:11000+1000=12000 共得21000+12000=33000#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#第四年:12000+1000=13000 共得33000+13000=46000#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#第五年:13000+1000=14000 共得46000+14000=60000#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#。#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#。#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#。#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#B工作(半年薪5000,每半年加薪300):#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#第一年:10000#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#一年半:5000+300=5300#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#兩年後:#ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#5300+300=5600#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl# 第二年累計:10000+5300+5600=20900<21000 A工作較B工作優100#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#DIV#ed_cl#兩年半:#ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#5600+300=5900#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#三年後:#ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#5900+300=6200#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl# 第三年累計:20900+5900+6200=33000=33000 雙方打平#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT color=#000000 size=2#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#三年半:#ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#6200+300=6500#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#四年後:6500+300=6800#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl# 第四年累計:33000+6500+6800=4630#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#0>46000 B工作較A工作優300#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#四年半:#ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#6800+300=7100#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#五年後:7100+300=7400#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl# 第五年累計:46300+7400+7700=61400>60000 B工作較A工作優1400#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl##ed_op#FONT color=#000000#ed_cl#往後持續暴增!#ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/FONT#ed_cl##ed_op#/FONT#ed_cl##ed_op#/DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#FONT size=1#ed_cl#J+W#ed_op#/FONT#ed_cl# 寫到:#ed_op#FONT size=2#ed_cl##ed_op#FONT color=#000000#ed_cl##ed_op#SPAN style="COLOR: red"#ed_cl#應要求題目改為:有兩項工作,一項是年薪1萬元,每年加薪1千元;另一項是半年薪5千元,半年加薪3百元。若要長久工作,您選哪一項工作?#ed_op#FONT color=#000000 size=3#ed_cl#
#ed_op#/P#ed_cl##ed_op#P#ed_cl#就題目給的條件#ed_op#/P#ed_cl##ed_op#P#ed_cl#一個第一年領11000元,每年增加1000元;一個第一年領10600元,之後每年增加600元,怎麼算都是前者划算啊,後者只會越差越多。#ed_op#/P#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl#yunhan 寫到:#ed_op#P#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN class=postbody#ed_cl##ed_op#FONT size=2#ed_cl#(9)半年薪,約在4年底就可以超過一年薪#ed_op#BR#ed_cl##ed_op#/FONT#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/P#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#P#ed_cl#
J+W 寫到:(5)“有一個人早上六點開始爬山﹐晚上六點到達山頂。第二天﹐他早上六點由原路開始下山﹐晚上六點到達山腳。在上山和下山時﹐這個人有多大的可能性在同一個時間經過了同一個地點﹖”
J+W 寫到:
早上六點由珊·法爾德島出發﹐中午12點到達蘭奇島,晚上六點到達聖·波普蘭島
星期天停駛
也就是說,每天的中午12點必定會經過蘭奇島這個地點
數年來都是如此,...........................................
可是有一天,海上列車的機件出了毛病,原因是引擎老舊造成故障,只能停駛漂浮在海上
(其實就是類似我說的休息時間! )
這時是星期二的上午11點,艾斯巴格(又譯:冰山,Iceberg,38歲)—Water-Seven市長,Galley-La Company社長,聽到消息後,趕緊派底下的船工,準備更新更快的
引擎到停駛地點,但是再怎麼快也必須花1個小時才能送到
那您覺得海上列車在中午12點經過蘭奇島的機率如何呢?
Anonymous 寫到:真的是100%啦
這跟平均速度無關
除非題目改成兩天都是由山下出發(相同方向)
才會有您所說的錯誤觀念產生
此時真的未必會於同時刻通過同地點(除了起訖點外)
但本題中 兩天是相反方向的
舉例來說
若兩天中皆於中午時分抵達接近山頂處
表示那人爬山時猛衝 但下山時整個上午都在閒晃
反之若兩天中皆於中午時分抵達接近山腳處
表示那人爬山時先甘後苦 但下山時猛衝再休息
平均速度相等完全不是重點
因為"兩人於同時刻到達同地點"不表示相遇前兩人走同樣遠
(別忘了 兩人並非同向喔)
再舉一例
個人覺得這題就有點像是:
兩人由線段不同兩端同時啟程 相向而行
速度快慢隨意 休息亦可
甚至是否同時抵達彼端都無妨
那兩人是否100%會在線段中某處(當然同時)擦肩而過
答案應該更明顯吧
請諸位先進賜教
avaisking 寫到:第五題:
依時間點來看(不論日期),會在同一時間經過同一個地點的機率是百分之百
如經同一地點上山和下山時間不一樣吧
下山通常比較快吧,而且會快滿多的