PP3-1 DS(Q12,13,14,20,23,24)

[william0904]

12.Each of the 25 balls in a certain box is either red, blue,or white
and has a number from 1 to 10 painted on it . If one ball is to be selected at random from the box, what is the probability that the ball selected will either be white or have an even number painted on it?

(1) The probability that the ball will both be white and have an even number painted on it is 0.

(2) The probability that the ball will be white minus the probability that the ball will have an even number painted on it is 0.2

ANS:E

13. In the xy-plane,at what two points does the graph of y=(x+a)(x+b) intersect the x-axis?

(1) a+b=-1
(2) The graph intersects the y-axis at (0,-6)

ANS:C (我對這種題目最沒輒了，各位大大有沒有解題技巧啊？）

14. If ιand k are lines in the xy-plane, is the product of the slopes of t and k equal to -1

(1) Link ι passes through the origin and the point (1,2)
(2) Link k has x-intercept 4 and y-intercept 2

Ans:C

20. Beth's bank charges a service fee on regular checking account for each month in which the balance on the account falls below $100 at any time during the month. Did the bank charge a service fee on Beth's regular checking account last month?

(1) During last month, a total of $1000 was withdrawn from Beth's regular checking account.

(2) At the beginning of last month, Beth'sregular checking account balance was $500.

ANS:E

23.If M is a finite set of negative integers, is the total number of integers in M an odd number?

(1) The product of all the integers in M is odd

(2) The product of all the integers in M is negative

ANS:B

24. An insurance company has a contracr with a medical laboratory to pay a discounted price for a certain medical test performed on patients referred to the laboratory by the insurance company. If the laboratory's original bill for this medical test on a patient referred by the insurance company is $230, what is the percent discount specified by the contract between the laboratory and the insurance company?
(1) The insurance company is required to pay only 20% of the original bill for the test.

(2)The insurance company is required to pay $46 for the test.

ANS:D

[william0904]

請幫幫我！！

[william0904]

3天過去了，都沒人肯幫我嗎

我需要有人教我這幾題啊

[Huang Hsin-Yi]

23.If M is a finite set of negative integers, is the total number of integers in M an odd number?

(1) The product of all the integers in M is odd

(2) The product of all the integers in M is negative

這題看起來比較短,我來試試!!!

M是一連串負數的組合,問m裡的數字數目加起來是否為奇數?

(1)只能確定所有的數字都是odd,並不能確定有幾個數字---insufficient
例如:-3,-5 the product=15
-3,-5,-7 the product=-105
(2)所有負數相承 偶數個為正-------------------------------sufficient
奇數個為負

Ans:B

另外發帖有一點建議---務必一題一帖
理由有二

1.太多題一帖,因為要戰友花很多時間才能完成一帖,很沒成就感,回覆率降低
2.一題一帖,才能便於後人查詢

[william0904]

ㄜ....這只有題目ㄟ
為啥是A呢

[Huang Hsin-Yi]

20. Beth's bank charges a service fee on regular checking account for each month in which the balance on the account falls below $100 at any time during the month. Did the bank charge a service fee on Beth's regular checking account last month?

(1) During last month, a total of $1000 was withdrawn from Beth's regular checking account.

(2) At the beginning of last month, Beth'sregular checking account balance was $500.

銀行帳戶若低於100會被收手續費,問Beth有無被收
(1)只說總共被提1000,又沒說存款多少
(2)只說剛開使有500,無法得知之後存提情況

(1)(2) 沒交代存提情況 所以無法得知

[william0904]

下次我會分開問的
因為要問的實在是太多了
可惡的DS...
剩下的幾題可以請各位大大幫我忙嗎
感激不盡！

[sunnyblue13s]

你可以把它分開重新提問嗎??

你分開過後....我也比較好幫你回覆.....

不然~~真的想幫忙.....看到題目.....也會頭昏的.....

[william0904]

晚點再分開問
要不是想問的題目太多...
我也不想連著問啊...