巍哥数学-GRE数学第三次直播.pptVIP

8. Mike, Scott, Jim, Kate and Pete each have a different number of assignments this month. Pete has fewer assignments than Kate, Kate has more assignments than Mike, Mike has more assignments than Jim, and Jim has more assignments than Scott. Which of the following could be the person who has the median number of assignments this month for the five people listed? Indicate all such answers. A. Mike B. Scott C. Jim D. Kate E. Pete 正确答案：ACE 9. T={2, 3, 5, 6, 7, 8, 9} Quantity A Quantity B The total number of positive 4-digit integers that can be formed where each digit is in set T and the 7·6·5·4 4 digits in each 4-digit integer are different from each other A. Quantity A is greater. B. Quantity B is greater. C. The two quantities are equal. D. The relationship cannot be determined from the information given. 正确答案：C 10. A certain class of 90 students took a typical proficiency test. The average (arithmetic mean) score of the students who passed the test was 84, and the average score of the students who failed the test was 60. If the average score of all students was 80, how many students passed the test? A. 15 B. 20 C. 42 D. 70 E. 75 正确答案：E 11. A research report states that the average (arithmetic mean) of 120 measurements was 72.5, the greatest of the 120 measurements was 92.8, and the range of the 120 measurements was 51.6. The information given above is sufficient to determine the value of which of the following statistics? Indicate all such statistics. A. the least of the 120 measurements B. the median of the 120 measurements C. the standard deviation of the 120 measurements D. the sum of the 120 measurements 正确答案：AD 12. The average (arithmetic mean) of the two numbers 3x and 3y is 48. Quantity A Quantity B The average of the two 30 numbers 2x and 2y A. Quantity A is greater. B. Quantity B is greater. C. The two quantities are