OG19新题 题目总数：142 做题总人数：7915 平均准确率：74.7%
Let S be the set of all positive integers having at most 4 digits and such that each of the digits is 0 or 1 What is the greatest prime factor of the sum of all the numbers in S?
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【OG20-P801-845题】Tides typically range from three to six feet, but while some places show no tides at all, some others, such as the Bay of Fundy, have tides of at least thirty feet and more.
A store currently charges the same price for each towel that it sells. If the current price of each towel were to be increased by $1,10 fewer of the towels could be bought for $120, excluding sales tax. What is the current price of each towel?
【OG20-P283-345题】Jack wants to use a circular rug on his rectangular office floor to cover two small circular stains, each less thansquare feet in area and each more than 3 feet from the nearest wall. Can the rug be placed to cover both stains?（1）Jack’s rug covers an area of 9π square feet.（2）The centers of the stains are less than 4 feet apart.
Since digital recording offers essentially perfect reproduction—on compact discs, digital audiotapes, ordigital videodiscs—audiophiles can accumulate vast collections of music, transferring them from oneformat to another, copying it, and digitally altering it with little effort and not damaging the sound quality.
【OG20-P604-745题】Although the discount stores in Goreville's central shopping district are expected to close within five years as a result of competition from a Spendless discount department store that just opened, those locations will not stay vacant for long. In the five years since the opening of Colson's, a nondiscount department store, a new store has opened at the location of every store in the shopping district that closed because it could not compete with Colson's. Which of the following, if true, most seriously weakens the argument?
Guillemots are birds of Arctic regions. They feed on fish that gather beneath thin sheets of floating ice, and they nest on nearby land. Guillemots need 80 consecutive snow-free days in a year to raise their chicks, so until average temperatures in the Arctic began to rise recently, the guillemots’ range was limited to the southernmost Arctic coast. Therefore, if the warming continues, the guillemots’ range will probably be enlarged by being extended northward along the coast.Which of the following, if true, most seriously weakens the argument?
Over the course of the eighteenth century, the average output of ironwork tripled as a result of several improvements in blowing machinery and because coal replaced charcoal as the fuel used in the smelting of iron ore.
The current economic downturn has significantly reduced advertising income both for business journals as well as general consumer magazines, especially if focusing on technology.
A popular beach has long had a dolphin feeding program in which fish are given to dolphins several times a day; many dolphins get as much as half of their food each day there. Although dolphins that first benefit from the program as adults are healthy and long-lived, their offspring have a lower life expectancy than offspring of dolphins that feed exclusively in the wild. Which of the following, if true, most helps to explain the lower life expectancy of offspring of dolphins feeding at the beach compared to other young dolphins?
It was only after Katharine Graham became publisher of The Washington Post in 1963 that it moved into the first rank of American newspapers, and it was under her command that the paper won high praise for its unrelenting reporting of the Watergate scandal.