請教一題計量

[汪汪北鼻]

Jeff drove to work from his home, averaging 40miles per hour, and was 12mins late. The next day he left home for work at the same time, took the same route, averaging 48 miles per hour, and was 7 minutes late. How far in miles is it from Jeff’s home to his work?
(A)20
(B)24.5
(C)30
(D)37.5
(E)40
Ans :A

[魚]

設 預定到達所花費的時間為T , 間距為L

L= (40/60) X (T+12)....................(1)

L= (48/60) X (T+7)...................... (2)


(1) (2) 聯立=> T = 18....................(3) 代入 (1) or (2)

=> L=20 #

[汪汪北鼻]

”惑”然開朗　 (H)

[汪汪北鼻]

*Exclusive of tax, was the total revenue from the sale of book x last week greater than 100?
1. last week more than 9 copies of book x were sold
2. Last week the revenue form the sale of each copy of book x was $10.50 plus tax.
Ans.. C
1.2是無法單獨解出，由1.2同時考慮時，我的算法是9*10.50/1.05=90 但是由於第一選項提到more than 9 那是不是表示可能會超過九本呢，如果超過九本那就是比100大了，所以可能比100大也可能比100小嚕，為什麼不選E呢?

*In country x each taxpayer files, either individually or jointly, one federal tax return per year. Did more that 10 million of the taxpayer who filed a federal tax return for 1984 report having individual retirement accounts?
.1.of the 90 million federal tax returns filed for 1984 in country x, 1/3 were joint returns filed by two taxpayers, all other returns were filed by individual taxpayers
2. of the country x taxpayers who filed federal tax returns in 1984, exactly 10.5 percent reported having individual retirement accounts
ans c
這題我題目實在看不懂

*if S is a set of integers and 5 is in s, is every multiple of 5 in S?
1. if x is in S , then x+5 is in S
2. if x is in S, then x-5 is in S
ansC
這題我題目也實在看不懂

[魚]

*In country x each taxpayer files, either individually or jointly, one federal tax return per year. Did more that 10 million of the taxpayer who filed a federal tax return for 1984 report having individual retirement accounts?
.1.of the 90 million federal tax returns filed for 1984 in country x, 1/3 were joint returns filed by two taxpayers, all other returns were filed by individual taxpayers
2. of the country x taxpayers who filed federal tax returns in 1984, exactly 10.5 percent reported having individual retirement accounts
ans c

本題講 "退稅"
X國的稅制有單獨跟合併計算兩種 , 一年期.試問 有超過10million 的人是單獨+退休滴嗎 ?

[homaru]

*Exclusive of tax, was the total revenue from the sale of book x last week greater than 100?
1. last week more than 9 copies of book x were sold
2. Last week the revenue form the sale of each copy of book x was $10.50 plus tax.
Ans.. C
1.2是無法單獨解出，由1.2同時考慮時，我的算法是9*10.50/1.05=90 但是由於第一選項提到more than 9 那是不是表示可能會超過九本呢，如果超過九本那就是比100大了，所以可能比100大也可能比100小嚕，為什麼不選D呢?

我會選Eㄟ,題目問不含稅的銷售額是否大於100
1)只知賣超過9本-->10本(含)以上
2)每本含稅價$10.5.....沒講稅率,不知道未稅價一本多少
有可能一本未稅$10.1也有可能一本$8
兩條件合併也不充分~

[homaru]

*if S is a set of integers and 5 is in s, is every multiple of 5 in S?
1. if x is in S , then x+5 is in S
2. if x is in S, then x-5 is in S
這題我題目也實在看不懂

問是否每個5的倍數都在set S內
1)x在S內,x+5也在S內-->5,10,15,20......都在S內
2)X在S內,x-5也在S內-->5,0,-5,-10....都在S內

5的倍數可正可負,唯有兩條件合併才能包括所有5的倍數
我選C

[汪汪北鼻]

*if S is a set of integers and 5 is in s, is every multiple of 5 in S?
1. if x is in S , then x+5 is in S
2. if x is in S, then x-5 is in S
這題我題目也實在看不懂

問是否每個5的倍數都在set S內
1)x在S內,x+5也在S內-->5,10,15,20......都在S內
2)X在S內,x-5也在S內-->5,0,-5,-10....都在S內

5的倍數可正可負,唯有兩條件合併才能包括所有5的倍數
我選C

小龍哥，你選對了 (H) ，不過我不清楚題目的意思，我的解讀是-如果s是整數的集合，而5這數學也在此集合內，那是不是5的倍數都在S內呢?
你的算法是把X當成5嗎?

[汪汪北鼻]

*Exclusive of tax, was the total revenue from the sale of book x last week greater than 100?
1. last week more than 9 copies of book x were sold
2. Last week the revenue form the sale of each copy of book x was $10.50 plus tax.
Ans.. C
1.2是無法單獨解出，由1.2同時考慮時，我的算法是9*10.50/1.05=90 但是由於第一選項提到more than 9 那是不是表示可能會超過九本呢，如果超過九本那就是比100大了，所以可能比100大也可能比100小嚕，為什麼不選e呢?

我會選Eㄟ,題目問不含稅的銷售額是否大於100
1)只知賣超過9本-->10本(含)以上
2)每本含稅價$10.5.....沒講稅率,不知道未稅價一本多少
有可能一本未稅$10.1也有可能一本$8
兩條件合併也不充分~

這題我也選E，不過答案確是C，一定是我們題目那解讀錯了

[吳志道]

這題我看到也會選Eㄅ....不過題供一個C的想法
當B為
(1) Last week the revenue form the sale of each copy of book x was $10.50 [plus tax. ] Revenue10.50 + tax .........所以C
(2)2. Last week the revenue[ plus/include... tax]form the sale of each copy of book x was $10.50 . Revenue+ tax =10.50 ........所以E

希望大家討論^^