GMAT考试数学辅导04年1月数学机井总结(三)(2)
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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,(4,5) (5,4); (-4,5)(-5,4);(4,-5)(5,-4); (-4,-5)(this one is not sure); (0,-6)
问从这八个点中任取一个点,x+2y>0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/(27^y), 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?(1FEET = 12 INCH) --》我的答案是600
73.N>K?
(1) N < 5K - 30
(2) K<30
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?
(1) at least one of the integers is negative
(2) 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 x>1 and y>1, is x (1) x^2/(xy+x)<1
(2) xy/(y^2-y)<1
ans: e