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OG15 OG16 OG17 OG18 OG19 OG20 OG2022
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Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck" -at some time in the past our ancestors suffered an event, greatly reducing their numbers and thus our genetic variation.
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OG15 OG16 OG17 OG18 OG19 OG20 OG2022
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Most efforts to combat such mosquito-borne diseases like malaria and dengue have focused either on the vaccination of humans or on exterminating mosquitoes with pesticides.
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数论
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If s and t are positive integers such that $$\frac{s}{t}={64.12}$$ which of the following could be the remainder when s is divided by t ?
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Of the 84 parents who attended a meeting at a school, 35 volunteered to supervise children during the school picnic and 11 volunteered both to supervise children during the picnic and to bring refreshments to the picnic. If the number of parents who volunteered to bring refreshments was 1.5 times the number of parents who neither volunteered to supervise children during the picnic nor volunteered to bring refreshments, how many of the parents volunteered to bring refreshments?
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PREP07 Test 1
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Beth's bank charges a service fee on a regular checking account for each month in which the balance on the account falls below $100 at any time during the month. Did the bank charge a service fee on Beth's regular checking account last month?(1)During last month, a total of $1,000 was withdrawn from Beth's regular checking account.(2)At the beginning of last month, Beth's regular checking account balance was $500.
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 In the figure above, segments PQ and PR are each parallel to one of the rectangular coordinate axes. What is the sum of the coordinates of point P ?(1)The x - coordinate of point Q is -1.(2)The y - coordinate of point R is 1.
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If x = kc and y = kt, then y - x =
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PREP07 Test 1
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In 1990 the budgets for projects Q and V were $660,000 and $780,000, respectively. In each of the next 10 years, the budget for Q was increased by $30,000 and the budget for V was decreased by $10,000. In which year was the budget for Q equal to the budget for V ?
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PREP07 Test 1
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Company C has a machine that, working alone at its constant rate, processes 100 units of a certain product in 5 hours. If Company C plans to buy a new machine that will process this product at a constant rate and if the two machines, working together at their respective constant rates, are to process 100 units of this product in 2 hours, what should be the constant rate, in units per hour, of the new machine?
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PREP07 Test 1
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An insurance company has a contract with a medical laboratory to pay a discounted price for a certain medical test performed on patients referred to the laboratory by the insurance company. If the laboratory's original bill for this medical test on a patient referred by the insurance company is $230, what is the percent discount specified by the contract between the laboratory and the insurance company?(1)The insurance company is required to pay only 20 percent of the original bill for the test.(2)The insurance company is required to pay $46 for the test.
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PREP07 Test 1
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Did it take Pei more than 2 hours to walk a distance of 10 miles along a certain trail? (1 mile = 1.6 kilometers, rounded to the nearest tenth.)(1)Pei walked this distance at an average rate of less than 6.4 kilometers per hour.(2)On average, it took Pei more than 9 minutes per kilometer to walk this distance.
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If I and k are lines in the xy-plane, is the product of the slopes of I and k equal to -1 ?(1)Line I passes through the origin and the point (1, 2).(2)Line k has x-intercept 4 and y-intercept 2.
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 The table above shows the results of a recent school board election in which the candidate with the higher total number of votes from the five districts was declared the winner. Which district had the greatest number of votes for the winner?
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PREP08 Test 1
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The passage suggests that the use of patents as bargaining chips to ward off infringement suits
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PREP07 Test 1
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According to the directions on a can of frozen orange juice concentrate, 1 can of concentrate is to be mixed with 3 cans of water to make orange juice. How many 12-ounce cans of the concentrate are required to prepare 200 6-ounce servings of orange juice?
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PREP07 Test 1
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Is x less than 20 ?(1)The sum of x and y is less than 20.(2)y is less than 20.
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PREP07 Test 1
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In the finite sequence of positive integers $${K}_{1}$$, $${K}_{2}$$, $${K}_{3}$$....,$${K}_{9}$$each term after the second is the sum of the two terms immediately preceding it. If $${K}_{5}= 18$$, what is the value of $${K}_{9}$$?(1) $${K}_{4}={11}$$(2) $${K}_{6}={29}$$
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If xy = -18, is x less than y?(1)x<0(2)y<10
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PREP07 Test 1
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At a certain restaurant, if each hamburger costs the same amount, what is the cost, excluding sales tax, of 1 hamburger?(1)The total cost, including a 6 percent sales tax, is $4.77 for 3 hamburgers.(2)The total cost, including a 6 percent sales tax, is less than $6.50 for 4 hamburgers.
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PREP07 Test 1
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The manager of a theater noted that for every 10 admission tickets sold, the theater sells 3 bags of popcorn at $2.25 each, 4 sodas at $1.50 each, and 2 candy bars at $1.00 each. To the nearest cent, what is the average (arithmetic mean) amount of these snack sales per ticket sold?
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