GMAT考试数学辅导04年1月数学总结(三)

　　58.给出一个柱形图，横坐标是六至十二月的平均每日用电量。 纵坐标是千瓦。 每月头600度电每度$0。14，超过的每度$0。11。 求八月的cost.

　　59.给出一个柱形图，横坐标是working hours,纵坐标是人数。 求working hours 的median.

　　60.DS, 不放回抽样，共有English and Spanish 良种，抽两本，问抽得at least one english book的概率。

　　1)english 与spanish 的比是1：3

　　2)书的总数少于20本

　　61.scientist studies the migration trend of a group of geese. The group contains 30% male geese. Among the geese that later on migrated, 20% are male. What is the ratio of migration factor for male geese to the migration facotr for female geese?

　　Solution: Assume total geese X, of which Y migrated.

　　The answer is simple / = ...

　　62.Some guy has 6 albums of anthology from which he read one poem at least. All peoms in the albums are different. Did he read more than 6 poems from at least one of the album?

　　a) he has read 22 poems in total.

　　b) the numbers of poems he read from each album are all distinct.

　　Anwser: C

　　63. k, l, m are positive integers, does k has more prime factors than m

　　a) k = 30l

　　b) m = 10^k

　　Answer: C

　　64.sqrt{2sqrt + 2/}

　　Answer: 4

　　65.two right cylinders, A and B. radius of A is 2 times radius of B. height of A is half the height of B. If Bs radius is x and Bs height is y. What is the difference between surface area of A and that of B.

　　Solution:

　　As suface 2pi^2 + pi2

　　Bs surface 2pix^2y + pi2xy

　　Difference = As - Bs

　　66.三角形, 有图, 一底角60度,另一底角45度角, 45度角所队边长10,求60度角所队边长为多少.

　　答案: 5根号6

　　67.某人去商店买东西,1/2买了a, 1/3 for b, 1/10 for c, and the rest $6 for candy. ask the total.

　　ans: 90 68.five letters d, i, i, g, t,排列组合，且两个i不相邻，求有多少种做法。

　　我的答案：36

　　69.坐标系中，有八个点， ; ;; ;

　　问从这八个点中任取一个点，x+2y0的概率是多少?　答案有1/8,1/4,etc

　　70.速度50miles per hour, if traveled 700feet, ask how many seconds used. 1mile=5280feet

　　71.81^x=1/, ask y in terms of x. ans: y=-4x/3

　　72.有一块地长15FEET，宽10FEET，用6INCH的SQUARE来铺，最少用多少块? --》我的答案是600

　　73.NK?

　　 N 5K - 30

　　 K30

　　我选的E

　　74.有12个数字，不是偶数，就是可以让5整除，其中又5个可以让2整除，由8个可以让5整除，问多少个可以被10整除?

　　75.what is the sum of a certain pair if consecutive odd integers?

　　 at least one of the integers is negative

　　 at least one of the integers is positive

　　ans: c

　　76.if y is the smallest positive integer such that 3150 multiplied by y is the square of an integer, then y must be:

　　a.2 b. 3 c.7 d. 4 e. 14

　　ans: e.14

　　77.the surface of a certain planet reflects 80 percent of the light that strike it. the clouds around the planet then absorb 40 percent of the reflected light. what percent of the light that strikes the planet is reflected from the surface and passes trough the clouds without being absorbed?

　　ans: 40%

　　78.if x1 and y1, is x x^2/1

　　 xy/1

　　ans: e