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190113
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A truck is used to transport olive oil. The density of olive oil is 50 pounds/feet³. The cylindrical tank of the truck is 6 feet in diameter and 9 feet in length. The empty truck is 11000 pounds. How many tons is the truck when it is full of olive oil? (1 ton = 2204.62 pounds)
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191031
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There are n different books in a shelf. What is the value of n?
(1)There are only two books of mathematics, and if these two different mathematics books are adjacent, the arrangements of these n books are 240.
(2)If two books are selected randomly from the shelf, there are 15 different combinations.
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PREP2012
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The recent rise of low-cost airlines in Country Y has led to great increases in the number of air travelers and flights. However, a “hidden cost” of flying and certain other forms of travel is the significant amount of air pollution, which contributes to global warming. To make people pay these hidden costs—and in the process discourage the explosive growth in flying—the government of Country Y plans to impose fees on all air travel. There is a problem, however, in that many residents of Country Y would then use automobile transportation instead, without paying the hidden costs of the resulting air pollution.Which of the following additions to the government's plan would be likely to help most in overcoming the problem referred to in the final sentence above?
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Magoosh
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 In the diagram above, coordinates are given for three of the vertices of quadrilateral ABCD. Does quadrilateral ABCD have an area greater than 30?Statement #1: point B has an x-coordinate of 4Statement #2: quadrilateral ABCD is a parallelogram
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OG18-数学分册
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 In the rectangular coordinate system shown above, points O, P, and Q represent the sites of three proposed housing developments. If a fire station can be built at any point in the coordinate system, at which point would it be equidistant from all three developments?
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An office supply store received a shipment of boxes of pencils. How many pencils were in the shipment altogether? (1 gross = 12 dozen)(1) The number of boxes of pencils in the shipment was 6 gross.(2) There were 3 dozen pencils in each box of pencils in the shipment.
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PREP07 Test 1
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At a certain pet shop,$$\frac{1}{3}$$ of the pets are dogs and $$\frac{1}{5}$$ of the pets are birds. How many of the pets are dogs?(1)There are 30 birds at the pet shop.(2)There are 20 more dogs than birds at the pet shop.
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KMFDS
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If positive integer $${n}\le{3}$$ and n is the number of times a coin is flipped, what is the value of n?(1) The probability of getting heads exactly once is $$\frac{1}{2}$$.(2) The probability of getting at least one tail is greater than $$\frac{1}{2}$$.
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PREP07 Test 1
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If there are more than two numbers in a certain list, is each of the numbers in the list equal to 0 ?(1) The product of any two numbers in the list is equal to 0.(2) The sum of any two numbers in the list is equal to 0.
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191222
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Now there is a coordinate system, and it is known that the coordinates of the two points are D (8, -2) and B (2,4). What is the coordinate of the intersection point of the vertical bisector of the DB and the x axis?
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OG12 OG15
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In Jefferson School, 300 students study French or Spanish or both. If 100 of these students do not study French, how many of these students study both French and Spanish?(1)Of the 300 students, 60 do not study Spanish.(2)A total of 240 of the students study Spanish.
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OG12 OG15
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 In the rectangular coordinate system above, the line y = x is the perpendicular bisector of segment AB (not shown), and the x-axis is the perpendicular bisector of segment BC (not shown). If the coordinates of point A are (2,3), what are the coordinates of point C ?
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OG18-数学分册
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During a certain bicycle ride, was Sherry's average speed faster than 24 kilometers per hour?( 1 kilometer = 1,000 meters)(1) Sherry's average speed during the bicycle ride was faster than 7 meters per second.(2) Sherry's average speed during the bicycle ride was slower than 8 meters per second.
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OG19-数学分册
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What is the average (arithmetic mean) annual salary of the 6 employees of a toy company?
(1) If the 6 annual salaries were ordered from least to greatest, each annual salary would be $6,300 greater than the preceding annual salary.
(2) The range of the 6 annual salaries is $31,500.
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OG19-数学分册
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The sequence $$s_1$$, $$s_2$$, $$s_3$$, ... , $$s_n$$, ... is such that $$s_n= \frac{1}{n} -\frac{1}{n+1}$$ for all integers $$n\geq 1$$. If k is a positive integer, is the sum of the first k terms of the sequence greater than $$\frac{9}{10}$$?
(1) $$k>10$$
(2) $$k < 19$$
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OG20 OG2022
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In the figure above, PQRT is a rectangle. What is the length of segment PQ ?
1.The area of region PQRS is 39 and TS = 6.
2.The area of region PQRT is 30 and QR = 10.
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300难题
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A country's per capita national debt is its national debt divided by its population. Is the per capita national debt of Country G within $5 of $500 ?
1. Country G`s national debt to the nearest $1,000,000,000 is $43,000,000,000.
2. Country G`s population to the nearest 1,000,000 is 86,000,000.
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190113 还原机经选题: 文字题&几何
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There are 21 employees in a company. According to the following conditions, can it be determined that the median annual salary of these people is less than $40,000?
1: The annual salaries of 12 people are less than $37,000.
2: The annual salaries of 9 people are greater than $41,000.
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Magoosh
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Aid workers have worried that residents of the Eastern Gobi Refugee Camp might be at risk for beriberi, a severe deficiency of Thiamine, a B vitamin. Thiamine is found in high concentrations in cereal grains, and many of the residents have grain free diets because of allergies. Doctors and nutritionists assigned to investigate the situation have disagreed, noting that the residents grow sustenance amounts of potatoes, kale, and cauliflower on the surrounding farm lands, and these foods provide substantial sources of Thiamine as well. Because the residents of this refugee camp do not have any allergies to any of these latter foods, and crops have been good because of favorable weather conditions, their risk of beriberi is much lower than originally thought.In the argument given, the two portions in boldface play which of the following roles?
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The most common metal in the Earth's crust, aluminum (or aluminium) was not discovered until 1825 because its isolated state is so reactive that free nuggets or flakes of the metal are never found in nature; rather, the metal is typically found as part of an amalgam, most commonly bauxite ore. Moreover, elemental aluminum is extremely difficult—and expensive—to separate from its ores by traditional chemical means. Indeed, the extreme reactivity of aluminum helps protect its modern, ubiquitous manifestations, such as aluminum foil. The surface of pure aluminum instantly combines with atmospheric oxygen to form a thin but robust “passivization” seal of aluminum oxide that prevents further corrosion. Many other metals, such as iron, are less reactive than aluminum, but their superficial oxides do not form as swiftly, completely, or impermeably.For several decades after its discovery, aluminum was considered a precious metal and was more costly than gold or platinum, not because of any fundamental scarcity, but because of its elevated cost of production. The price of aluminum suddenly plummeted in 1886, however, when two 23-year-old inventors independently developed an electrolytic process of separating pure aluminum from a bath of molten aluminum salts, primarily cryolite. Cryolite itself is rare enough that synthetic salts eventually replaced it as the solution medium.
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