Re: [問題]請問來欣的數學問題 M8 :)
※ 引述《officium (officium)》之銘言：
: M8
: 17
: In a nationwide poll, N people were interviewed.
: If 1/4 of them answered ”Yes” to Q1,
: and of those, 1/3 answered “Yes” to Q2,
: which of the following expressions
: represents the number of people interviewed who
: did not answer “Yes” to both Q?
他的意思應該是1/4的人在Q1回答yes,然後這些人當中又有1/3的人在Q2回答yes
最後他問有多少人沒有兩題都回答yes,所以答案應該是 N*(1-(1/4)*(1/3))=11N/12
: 30
: The organizers of a fair projected a 25% increase in
: attendance this year over
: that of last year, but attendance this year actually decrease by 20%.
: What percent of the projected attendance was the actual attendance?
假設去年的出席率是x 假設的是1.25x 實際的是0.8x
他問的是 0.8x/1.25x=64% (其實我也看不太懂題目,是照答案推的=.=)
: 22
: A hiker walked for 2 days, On the second day the hiker walked
: 2 hours longer and at an average speed 1 mile per hour faster
: than he walked on the first day. IF during the two days he walked
: a total of 64 miles and spent a total of 18 hrs walking, what
: was his average speed on the first day
: 我設第一天走 x小時 所以第二天 x+2
: 2x+2=18 x=8
到這邊沒問題 接著假設第一天的平均速率是v 所以第二天的是v+1
v*8+(v+1)*10=18v+10=64 v=3
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◆ From: 140.112.4.249
※ 編輯: tingting88 來自: 140.112.4.249 (06/01 17:35)
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