Re: [計量] JJ求解
※ 引述《zoo22 (zoo)》之銘言：
: 3. Pqst is a rectangle pq=3 pt=6; r is a pt on qt such that area of trapezium
: pqrt=12. what is the perimeter of trapezium pqrt?
題目怪怪的，r應該在qs上吧??
如果r在qs上，則可從梯形面積求出qr=2, rs=4
又可從直角三角形trs求出 tr=5
則梯形邊長 = qp + pt + tr + rq = 3 + 6 + 5 + 2 = 16
: 4. Which of the following is both the mean and the median of 7 consecutive
: integer so that the least of which is x.
: A. x+4
: B. x+3
: C. x+2
: D. x+28/7
: E. x+3/2
七個連續整數，所以是 x x+1 x+2 x+3 x+4 x+5 x+6，mean = median
答案是x+3
: 8. John traveled 80% of the way from Yellow-town to Green-fields by train
: at an average speed of 80 miles per hour. The rest of the way John
: traveled by car at an average speed of v miles per hour. If the average
: speed for the entire trip was 60 miles per hour, what is v in miles per
: hour?
: (a) 30
: (b) 40
: (c) 50
: (d) 55
: (e) 70
設整趟travel的總距離是D，則 v = 0.2D/[(D/60)-(0.8D/80)]
0.2D：剩下20%旅程的距離
(D/60)-(0.8D/80)：(整個旅程花的時間)-(前80%旅程花的時間)，
也就是剩下20%旅程所花的時間
如果覺得很複雜，其實可以隨便假設總距離是100，代進去算答案就出來了
答案是v=30
: 10.In a nationwide poll, N people were interviewed. If 1/4 of them answered
: "yes" to question 1, and of those, 1/3 answered "yes" to question2, which
: of the following expresions represents the number of people interviewed
: who did not answer "yes" to both questions?
: A : N/7
: B : 6N/7
: C : 5N/12
: D : 7N/12
: E : 11N/12
謝謝BlueKidds更正，是1/4的人中的1/3 say yes，所以答案是E囉
: 7. Out of 10 shirts, 2 are defective. 3 are selected, what is the
: probabiltiy that none is defective?
8/10 * 7/9 * 6/8 = 7/15
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11/02 11:25, , 1F
11/02 11:25, 1F
※ 編輯: choucow 來自: 61.217.194.2 (11/03 14:40)
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