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GMAT Exam
At a certain used-book store, the cost of each paperback book is x dollars and the cost of each hardcover book is y dollars. What is the cost of a hardcover book at the store?
(1)
At the store, the cost of 3 paperback books and 5 hardcover books is $12.25.
(2)
At the store, the cost of 9 paperback books and 15 hardcover books is $36.75.
In 90 percent of the commercial airline accidents last year, one or another of a group consisting of only 18 percent of the world's commercial airlines was involved. Since the other 82 percent of airlines were generally flying the same types of airplanes as the accident-prone airlines, significant differences in safety procedures must have been responsible for these differences In safety records.
Which of the following, if true about the world's commercial airlines last year, most seriously weakens the argument above?
