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191222
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N is an integer. Can (n-1)*n*(n+1) be divisible by 12？
Condition 1 :(n-1)(n+1) is even
Condition 2: n is odd
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200301
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O is the center of the square. As shown in the figure, a point moves from A to O, then to E and then to C. The other point moves from A to M and then straight to C. The distance of the two points is the same. What is the ratio of AM to BM?
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200301
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Is x a factor of 24?
(1)3x is a factor of 48
(2)5x is a factor of 60
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200301
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There are 8 people (3 men and 5 women), from which 3 people are selected to form a committee. How many combinations are there for at least one person is a man?
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200301
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If f(x)=$$x ^ { 2 } * ( 1 - x ) ^ { 2 }$$, what is f(1-x)?
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200301
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There are eight points in the plane, no three points in a straight line, how many triangles can be formed?
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200301
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Is a five-digit number “ababa” divisible by 3?
(1)a is divisible by 3
(2)b is divisible by 3
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200301
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A square has two circles, one big and one small, which are tangent to each other and are all tangent to the square. The radius is R and r respectively. What is the length of the diagonal of the square?
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200301
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x is a two-digit number, and the unites digit of x is greater than 1. What is the unites digit of x?
(1). the units digit of $$x^2$$ is the same as the units digit of x
(2). the units digit of $$x^3$$ is the same as the units digit of x
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200301
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There were two types of phone calls: the first type accounted for 80%, with an average call time of 2 minutes; the second type accounted for 20%, with an average call time of 3 minutes. How many seconds does the overall average call time more than 2 minutes?
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200301
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There is a rectangle. The sum of the areas of which two parts is the same as the sum of the areas of part 2 and part 8?
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200301
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What is the largest prime factor of 11! +12! +13! ?
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200301
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DS：∣2X-Y∣=∣2Y-X∣?
(1). X=Y
(2). Y>0
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200301
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(4!)^n is a factor of 12!, but (4!)^(n+1) is not a factor of 12!, what is the value of n?
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200301
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A sequence 1,2,3,4,5,11, x, and x is a positive integer, is x≥4?
(1). The median of the sequence is 4
(2). x ≥ the median of the sequence
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200301
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Which of the following is greatest?
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200301
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The length of the side of cube B is 2% longer than that of the side of cube A, and the volume of cube A is 8. What is the volume of cube B?
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200301 还原机经选题: 数论&代数
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If n, m, and k are positive integers, and $$\frac { 9 } { 10 } < \frac { 1 } { n } + \frac { 1 } { m } + \frac { 1 } { k } < 1$$, is n+m+k >11?
(1)n=2 and m=3
(2)k=7
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200301
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Six different letters are used to form a word. The letters in the first, second and fourth positions are definite. How many ways are there to form a word?
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200301 还原机经选题: 数论&代数
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If x and y are all real numbers，is x > 1？
1.x*$$\sqrt{y}$$ >1
2.$$\sqrt{x}$$*y < 1
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