題目

1. Points R, S, and T lie on a number line, where S is between R and T. The distance between R and S is 6, and the distance between R and T is 15.

Quantity A：the distance between the midpoints of lines segments RS and ST

Quantity B：the distance between S and T

A. Quantity A is greater.

B. Quantity B is greater.

C. The two quantities are equal.

D. The relationship cannot be determined from the information given.

正確答案：B

題目解析：Quantity A長(zhǎng)度為RT的一半，7.5，Quantity B長(zhǎng)度為15-6=9，因此選B。

2. x, y, and z are the lengths of the sides of a triangle.

Quantity A：x+y+z

Quantity B：2*z

A. Quantity A is greater.

B. Quantity B is greater.

C. The two quantities are equal.

D. The relationship cannot be determined from the information given.

正確答案：A

題目解析：兩邊之和大于第三邊，x+y>z. 所以x+y+z>2*z

3. Rectangle R has length 30 and width 10, and square S has length 5. The perimeter of S is what fraction of the perimeter of R ? ___/___

正確答案：20,80

題目解析：R周長(zhǎng)為80，S周長(zhǎng)為20，按照題目要求，前面填入20，后面填入80。根據(jù)OG解釋，考生如果約分為1/4也是正確的。

4.

1, –3, 4, 1, –3, 4, 1, –3, 4,..

In the sequence above, the first 3 terms repeat without end. What is the sum of the terms of the sequence from the 150th term to the 154th term?

正確答案：7

題目解析：題目說(shuō)前三項(xiàng)無(wú)限循環(huán)， 所以1，-3， 4 是一個(gè)循環(huán)。150th正好是4，然后以此類推，150th到154th的和 為4+ 1+(-3)+4+1=7

5.

For which of the following bird species is the standard deviation of the numbers of sightings shown for the four seasons least

A. Cardinal

B. Junco

C. Robin

D. Sparrow

E. Wren

正確答案：D

題目解析：此題解題要點(diǎn)有兩個(gè)，首先考生需要理解standard deviation也就是標(biāo)準(zhǔn)差的概念。其次標(biāo)準(zhǔn)差計(jì)算公式較為復(fù)雜，強(qiáng)行計(jì)算會(huì)花費(fèi)大量時(shí)間，因此需要省時(shí)解法，大家可以觀察各組數(shù)據(jù)找出四個(gè)數(shù)據(jù)差異小的一組，即為正確答案，因此選D。