190207
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How many zeros are there at the end of (3! + 4!)!
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190207
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All the students in one class took at least one course. There were 18, 18 and 20 students taking subjects A, B, and C, respectively. There were 9 people who took A and B courses simultaneously and 9 people took B and C courses. 4 students took three courses at the same time. How many people were there in this class?
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190207
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Is xy-z > x-yz?
1:y > 1
2:x > 0
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190207
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Is x < y ?
1:x > 0
2:$$x^{2}$$ < xy
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190207
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In rectangular ABCD, ab = 10, BC = 6. What is the area of the shaded area?
1:l=0.8
2:∠d=30°
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190207
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101*99+102*98+103*97=?
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190207
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A painter can choose one or more of the following six colors, red, yellow, blue, green, pink and white, to paint the house. How many combinations may contain white?
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190207
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(n-1)*n!+(n-1)!*n=?
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190207
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What is the sum of all four-digit numbers that can be composed of 1,2,3,4?
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190207
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The solutions of the equation $$x^{2}$$+mx+n=0 are 2 and 1. m-n=?
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190207
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Is the quadrilateral square?
1: The lengths of two diagonals are equal.
2: The two diagonals are perpendicular to each other.
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190207
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R, Q, S are positive integers greater than 1. Do R and Q have the same prime factor?
1: R and S do not have the same prime factor.
2: S and Q do not have the same prime factor.
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190207
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E is a point on the CD of a parallelogram ABCD, the area of which is three times that of the triangle ACE. What is the value of CE/CD=?
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190207
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There are three lines, Ax+y=1, Bx+y=2, Cx+y=3. A≠B, B≠C. How many intersections can these three lines form?
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190207
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c is a mixture of a and b. The unit price of c is $3.2/kg. What is the value of a/b=?
(The price is proportional to the unit)
1: The unit price of a is $2 / kg.
2: The unit price of b is $4 / kg.
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190207
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It takes 0.125mg of substance x to make a bucket of paint. There are 10g of this material in the warehouse. How many barrels of paint can be produced at most?
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190207
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A(2,8), B(8,-2). What is the abscissa of the point on the x-axis that can make The distance from this point to A is equal to that from this point to B
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190207
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The angle between a lighthouse and a ship is 30 degrees, and the tower height is 1500m. What's the distance between the lighthouse and the boat?
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190207
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The range of set a is 7, and the range of set B is 12. What is the minimum possible range of the union of AB?
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190207
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One machine can complete 800 units of work in 2.5 hours. How many machines can complete 7200 units of work in 8 hours?
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