PP-PS1完整详解版-V2[1].0

the vacation?

(A) $200 (B) $300 (C) $400 (D) $500 (E) $600

------------------------------------------------------------------------------------------------------------------------------------ 【答案】 E

【思路】平均分配給不同人造成每個人所需負擔的額度不同，故可用一方程式解決此問題

假設 Total cost 為 T

T4T3為3個人平均每個人需分攤的額度

T4為4個人平均每個人需分攤的額度

依題意得知 4個人平均分攤的額度比3個人少$50 故列下列方程式 -50 =

T4 ?解方程式得 T=600 ?答案E

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The table shows the number of red blood cells per cubic millimeter of blood for each of five people. What is the median number of red blood cells per cubic millimeter of blood for these people?

(A) 4,600,000 (B) 5,000,000 (C) 5,020,000 (D) 5,150,000 (E) 5,300,000 129. 12981-!-item-!-187;#058&009035

The table above shows the number of days worked by a certain sales representative in each of three

months last year. If the number of sales calls that the representative made each month was proportional to the number of days worked in that month and if the representative made a total of 168 sales calls in the three months shown, how many sales calls did the representative make in August?

(A) 50 (B) 51 (C) 56 (D) 57 (E) 60 130. 13409-!-item-!-187;#058&009269

[?]

According to the table, the median acreage managed by the Federal Land Management agencies is how many million acres?

(A) 87 (B) 92 (C) 133 (D) 191 (E) 270 131. 13459-!-item-!-187;#058&009437

If the speed of x meters per second is equivalent to the speed of y kilometers per hour, what is y in terms of x ?

(1 kilometer = 1,000 meters)

(A) 5x/18 (B) 6x/5 (C) 18x/5 (D) 60x

(E) 3,600,000x 132. 13505-!-item-!-187;#058&009469

If d is the standard deviation of x, y, and z, what is the standard deviation of x + 5, y + 5, and z + 5 ?

(A) d (B) 3d (C) 15d (D) d + 5 (E) d + 15

------------------------------------------------------------------------------------------------------------------------------------ 【答案】 A

【思路】 要了解到標準差的概念

標準差的公式?

標準差S=(1/nΣXi^2-X^2)^(1/2) n=樣本數 X=平均數

標準差對平均數是很重要的。

因為它提供了資料分布廣度的參考價值。

當樣本值等量增加代表平均數亦是等量增加，故標準差不變 ? 答案A 當然，帶公式也會發現值是不變的啦XD

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A student worked for 20 days. For each of the amounts shown in the first row of the table, the second row gives the number of days that the student earned that amount. What is the median amount of money that the student earned per day for the 20 days?

(A) $96 (B) $84 (C) $80 (D) $70 (E) $48

134. 13655-!-item-!-187;#058&009647

A 4-person task force is to be formed from the 4 men and 3 women who work in Company G's human

resources department. If there are to be 2 men and 2 women on this task force, how many different task forces can be formed?

(A) 14 (B) 18 (C) 35 (D) 56 (E) 144

------------------------------------------------------------------------------------------------------------------------------------ 【答案】 B

【思路】 排列組合的概念，從一群人中分別挑出兩男兩女作組合，可以產生多少組合

43C2?C2?6?3?1810n ?有18種不同的組合 ?答案 B

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For each of her sales, a saleswoman receives a commission equal to 20 percent of the first $500 of the total amount of the sale, plus 30 percent of the total amount of the sale in excess of $500. If the total amount of one of her sales was $800, the saleswoman's commission was approximately what percent of the total amount of the sale?

(A) 22% (B) 24% (C) 25% (D) 27% (E) 28%

------------------------------------------------------------------------------------------------------------------------------------ 【答案】 B

【思路】 本題該注意 30%那部分是只有算在超過$500元的部分，意思就是 超過部分減去$500才會是多的commission < plus 30 percent of the total amount of the sale in excess of $500> 故 方程式可列為 500?20%?(800?500)?300??24% 800800?答案B ------------------------------------------------------------------------------------------------------------------------------------ 136. 13806-!-item-!-187;#058&009738

If $10,000 is invested at x percent simple annual interest for n years, which of the following represents the total amount of interest, in dollars, that will be earned by this investment in the n years?

(A) (B) (C) (D) (E) 137. 13906-!-item-!-187;#058&009755

If a equals the sum of the even integers from 2 to 20, inclusive, and b equals the sum of the odd integers from 1 to 19, inclusive, what is the value of a - b ?

(A) 1 (B) 10 (C) 19 (D) 20 (E) 21

------------------------------------------------------------------------------------------------------------------------------------ 【答案】 B

【思路】梯形公式可以解，一個是偶數從2到20的和，一個是奇數從1到19的和，求兩者的差。 解法一 ?(2?20)?10(1?19)?10??110?100?10 22解法二 ?每個奇偶數的差都是1? (2-1)+(4-3)…(20-19)= 10 ------------------------------------------------------------------------------------------------------------------------------------ 138. 14007-!-item-!-187;#058&009795

The cost to park a car in a certain parking garage is $8.00 for up to 2 hours of parking and $1.75 for each hour in excess of 2 hours. What is the average (arithmetic mean) cost per hour to park a car in the parking garage for 9 hours?

(A) $1.09 (B) $1.67 (C) $2.25 (D) $2.37 (E) $2.50

------------------------------------------------------------------------------------------------------------------------------------ 【答案】 C

【思路】 算術平均數的問題 首先看懂題意，兩小時內$8.00，超過兩小時每個小時$1.75，求9個小時的平均數 故可列式為 平均數= 8?[1.75?(9?2)]?2.25 ?答案 C 9------------------------------------------------------------------------------------------------------------------------------------ 139. 14108-!-item-!-187;#058&009811

A set of 15 different integers has a median of 25 and a range of 25. What is the greatest possible integer that could be in this set?

(A) 32 (B) 37 (C) 40 (D) 43 (E) 50

------------------------------------------------------------------------------------------------------------------------------------ 【答案】 D

【思路】

Range定義=最大值-最小值

題目問說哪個最有可能是最大值,所以從最大的先推推看

E)Max:50,range25代表Min=50-25=25 ==>可是25又是中位數,所以不可能!! D)Max:43,range25代表Min=43-25=18

列舉驗證一下: 18 19 20 21 22 23 24 25 ........43 總共15個,所以中位數左邊應該有7個 剛好25也是中位數,所以成立!! [另解]

因為range25,各選項間距為

=>(7~32)(12~37)(15~40)(18~43)(25~50)

由於15個不同的數字,此外,中位數為25=>只有D選項符合

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If x and y are integers and 3^(x - 4) = 3^(y + 2), what is y in terms of x ?

(A) x - 6 (B) x - 5 (C) x - 2 (D) x + 2