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Magoosh
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If the circle with center O has area 9π, what is the area of equilateral triangle ABC?
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Unlike Mercury and Mars, Venus has a dense, opaque atmosphere that prevents direct observation of its surface. For years, surface telescopes on Earth could glean no information about the surface of Venus. In 1989, the Magellan probe was launched to do a five-year radar-mapping of the entire surface of Venus. The data that emerged provided by far the most detailed map of the Venusian surface ever seen. The surface shows an unbelievable level of volcanic activity: more than one hundred large shield volcanoes, many more than Earth has, and a solidified river of lava longer than the Nile. The entire surface is volcanically dead, with not a single active volcano. This surface is relatively young in planetary terms, about 300 million years old. The whole surface, planet-wide, is the same age: the even pattern of craters, randomly distributed across the surface, demonstrates this. To explain this puzzling surface, Turcotte suggested a radical model. The surface of Venus, for a period, is as it is now, a surface of uniform age with no active volcanism. While the surface is fixed, volcanic pressure builds up inside the planet. At a certain point, the pressure ruptures the surface, and the entire planet is re-coated in lava in a massive planet-wide outburst of volcanism. Having spent all this thermal energy in one gigantic outpouring, the surface cools and hardens, again producing the kind of surface we see today. Turcotte proposed that this cycle repeated several times in the past, and would still repeat in the future.
To most planetary geologists, Turcotte's model is a return to catastrophism. For two centuries, geologist of all kinds fought against the idea of catastrophic, planet-wide changes, such as the Biblical idea of Noah's Flood. The triumph of gradualism was essential to the success of geology as a serious science. Indeed, all features of Earth's geology and all features of other moons and planets in the Solar System, even those that are not volcanically active, are explained very well by current gradualist models. Planetary geologists question why all other objects would obey gradualist models, and only Venus would obey a catastrophic model. These geologists insist that the features of Venus must be able to be explained in terms of incremental changes continuously over a long period. Turcotte, expecting these objections, points out that no incremental process could result in a planet-wide surface all the same age. Furthermore, a slow process of continual change does not well explain why a planet with an astounding history of volcanic activity is now volcanically dead. Turcotte argues that only his catastrophic model adequately explains the extremes of the Venusian surface.
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Magoosh
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There are 13 hearts in a full deck of 52 cards. In a certain game, you pick a card from a standard deck of 52 cards. If the card is a heart, you win. If the card is not a heart, the person replaces the card to the deck, reshuffles, and draws again. The person keeps repeating that process until he picks a heart, and the point is to measure how many draws it took before the person picked a heart and, thereby, won. What is the probability that one will pick the first heart on the third draw or later?
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Magoosh
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If a right triangle has area 28 and hypotenuse 12, what is its perimeter?
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Magoosh
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For the first 5 hours of a trip, a plane averaged 120 kilometers per hour. For the remainder of the trip, the plane travelled an average speed of 180 kilometers per hour. If the average speed for the entire trip was 170 kilometers per hour, how many hours long was the entire trip?
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Magoosh
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The author is primarily concerned with:
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Magoosh
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P and Q are both positive integers. When P is divided by Q, the remainder is some positive integer D, and when P is divided by (Q + 3), the remainder is also D. If $$\frac{P}{Q}$$ = 1020.75 and$$\frac{ P}{(Q + 3)}$$ = 816.6, then which of the following gives the correct set of {D, Q}?
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Magoosh
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A computer can perform c calculations in s seconds. How many minutes will it take the computer to perform k calculations?
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The proliferation of social media tools allowing for communication within corporations has recently been the subject of two studies. Meyers and Tassleman find that such tools tend to exert a positive effect but that such effect tends to diminish the larger the organization. The two speculate that one of the reasons is that the kind of communication in social media presumes a level of comfort that is not consistent with that typically found in larger companies. Consequently, many employees are reluctant to use social media tools because they feel constrained by a workplace culture that is not consistent with the social values these tools promote. Such a result undermines the very relaxed spirit that upper level management hopes to foster by using such tools.
Gershin focuses on the extent to which social media tools have displaced other forms of office communication, notably email and in-person interactions. Additionally, he uses data collected from surveys, from both middle management and upper management, to assess the effect, if any, that such displacement has had. His findings are twofold: social media is in many cases deemed extraneous since it adds a layer of redundancy to communication. In other words, employees have adequately communicated something via traditional channels, but simply echo such communication on social network channels. However, Gershin found that social media tools fostered company culture because these tools provided employees a means of planning social events, something they might not have done using traditional forms of communication.
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Magoosh
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Which of the following, if true, best calls into question the validity of Gershin's findings regarding the effect of social media tools in the workplace?
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Magoosh
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Forty miles to the west of Tucson, a developer attempted to develop an "oasis" glade in the Sonoran Desert. He created a glade that, the developer claims, is as lush and plant-filled as the ambient 35° C temperatures allow. In particular, the developer planted several native fruit-bearing plants, such as prickly-pear cactus. Once the glade was established, a number of desert birds and mammals would regularly inhabit the glade, often eating most of the fruit that falls from the plants. The considerations given best serve as part of an argument that:
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Magoosh
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If the average (arithmetic mean) of seven consecutive integers is k + 2, then the product of the greatest and least integer is
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Magoosh
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On a certain multiple-choice test, 9 points are awarded for each correct answer, and 7 points are deducted for each incorrect or unanswered question. Sally received a total score of 0 points on the test. If the test has fewer than 30 questions, how many questions are on the test?
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Magoosh
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In the last decade, the country of Alumba has undergone a massive construction boom. In one city, Semanta, hundreds of new buildings have been erected and, as a result, the ambient light at night has increased from 0.10 lux to 10 lux, causing migratory birds flying to alter their traditional path and fly into Semanta, where they often crash into buildings. The mayor believes that to ensure the birds keep to their traditional flight path while flying through Alumba, the city should turn off lights throughout the city at night during the bird's migratory season, so that ambient light is around 0.10 lux. Which of the following, is necessary, to evaluate the mayor's proposal for limiting the amount of night light that Semanta emits?
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Magoosh
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Art Historian: Recently, computer analysis has revealed that a few of a famous Flemish artist's works are forgeries, and are actually the work of noted forger Elmyr de Hory. While such a development may emit violent reverberations through the art world, even those museums that have a wealth of the Flemish artists in their collections should not be overly concerned. Hundreds of this Flemish artist's works were tested to determine whether they were forgeries, yet only a slim few turned out to be actual forgeries. Thus, the master's reputation as one of the greatest artists humanity has ever produced will surely remain undiminished. Which of the following, if true, casts the most doubt on the art historian's conclusion?
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Magoosh
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If∠CFD=85° , then what is the value of x?Note: Figure not drawn to scale
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Magoosh
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If 2x - y = 10 and$$ \frac{x}{y} = 3$$, then x =
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Magoosh
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According to the passage, one reason a reptile may not be able to maintain activity at a suboptimal temperature is
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Magoosh
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The passage mentions the leatherback turtle in order to illustrate that
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Magoosh
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Scientists originally believed that asteroids lacked regolith because
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