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190415
|
It takes 12 hours for machine A to make 1200 parts alone. Machine B works at 1/10 of the speed of machine A. How long will it take if B makes 400 parts alone?
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190321
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Is x odd?
1: x is an integer.
2: (x+1)(x-1) is even.
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190415
|
What's the largest prime factor of 11!+12!+13!?
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190321
|
$$a_n=a_{n-1}+3(n \geq 1)$$.$$a_1=2$$. What's the remainder of $$a_{98}$$ when divided by 10?
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190321
|
$$\frac{1}{16^x+16^{-x}}$$=?
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190207
|
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
|
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
|
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
|
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
|
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
|
There are three points in the xy-plane, A(a, b), B(c, d), C(d,c). Is AB=AC?
1:($$a^{2}$$-$$b^{2}$$)($$c^{2}$$-$$d^{2}$$)=0
2:($$a^{2}$$+$$b^{2}$$)($$c^{2}$$+$$d^{2}$$)=0
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190207
|
The product of unit digit, tens-digit, and hundreds-digit of a three-digit number is 144. What is the tens-digit number when the three-digit number is minimum?
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190207
|
x,y are positive integers. (x-y)(x+y)=37.What is the value of y？
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190207
|
Three different numbers are chosen from the five numbers, 0,2,4,5,6, to form three-digit numbers. If this three-digit number is a multiple of 5, how many different combinations are there?
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190207
|
Is the y-intercept of line l greater than 4?
1: The intercept of line l is equal to that of line y = 2x + 3.
2: The slope of line l is 5
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190207
|
x,y are positive numbers. x$$y^{\frac{1}{2}}$$=?
1：$$x^{2}$$*y=13
2：x*$$y^{2}$$=14
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190603
|
Someone will pass four traffic lights of ABCD while driving to work, and the probability of stopping at the ABCD traffic lights is 50%, 40%, 30%, 30%, respectively. What is the probability that this person will only stop at BC traffic lights today?
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190603
|
The number of a bacteria triples every 30 minutes, how many times the number of the bacteria after 4 hours is the number of bacteria after 2 hours?
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190603
|
A company often needs to send employees on business trips, every time 10 employees are sent. This company intends to spend 3,000,000 yuan to buy a 10-seat private jet. The cost of this plane is 6,000 yuan per take-off. If the company don't t buy a plane, the company's staff will spend 1,000 yuan per flight. How many times will the plane fly to make it more cost-effective to buy a private jet?
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190603
|
DS: x> 1, is x / 3 an integer?
(1). 72 / x is an integer
(2). 81 / x is an integer
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