GRE数学易错题十例

GRE 数学易错题十例1，l1, l2 and l3 are three lines in space The number of points at The number of points at which lines l1 and l2 intersect which lines l2 and l3 intersect 1.三条任意直线，L1 和 L2 的交点的个数与 L2 和 L3 的交点的个数没关。 2. The number of 1/4-inch lengths in 1 a 4-inch length 2，是问 4 英尺中有多少个 1/4 英尺，应当是 16 个，所以是 A 3. The maximun number of solid cubes 4 having edges of length 1/2 meter that can be placed inside a cubical box having inside edges of length 1 meter 3 边长为 1 的立方体里最多能放下几个边长为 1/2 的立方体，当然是 8 个咯 4. Cube C has volume 8 cubic centimeters The area of one of the faces of cube C 3 square centimeters 4 立方体体积是 8，那一个面的面积当然是 4 咯 5. Ms.Smith got an 8 percent cost-of-living raise of $20 per week Ms.Smiths new weekly salary $260 5 x*0.08=20，那 x+20=270260 6. On a certain number live, if -7 is a distance of 4 from n and 7 is a distance of 18 from n then n= A.25 B.11 C.3 D.-3 E-11 6 应当是-11 7. For all real numbers a and b. if ab=a(a+b), then a(ab)= A. a2+ab B a2+ab+a C a2+a+b D a3+a2b E a3+a2b+a2 注：a2 表示 a 平方，a3 表示 a 立方 7新定义的运算ab=a(a+b), 那a(ab)=a(aa+ab)=a(a+aa+ab)=aa+aaa+aab 8.secretary typed 6 letters,each of which had either 1 or 2 pages.If the secretary typed 10 pages in all, how many of the letters had 2 pages? A 1 B 2 C 3 D 4 E 5 答案是 D，题目我都看不懂，是啥意思呢? 这是说秘书打六封信，没一封信要 1 页或者两页。假如秘书总共打了 10 页，那么有多少封信是两页? 解答：设有 x 封，则 2x+(6-x)=10,解得 x=4. 9 how many of the five numbers above are each equal to the product of an integer and an odd integer that greater than 1? 这五个数是:2 6 8 14 16 a.none b.one c.two d.there e.four 我觉得这道题除了 2 不行能,其它四个数都有可能.可答案是 c,想问大家为什么? 题目意思是这 5 个数哪些可以是 2 个 1 的数的积,一个是奇数,一个是整数,只有 6 和 14 的因数中有奇数,所以 C. 10 这句话大家看该怎样列式子呢?这是一道图表题. what was the approximate percent increase in personal income from 1965 to 1970? 是这样(1970-1965)/1965 还是(1970-1965)/1970 这样? 是这样:(1970-1965)/1965