Q10: A set of numbers has the property that for any number t in the set, t + 2 is in the set. If –1 is in the set, which of the following must also be in the set? I. -3 II. 1 III. 5 A. I only B. II only C. I and II only D. II and III only E. I, II, and III KEY: D,我选了E, 为什么I 不对？
Q25: A photographer
will arrange 6 people of 6 different heights for photograph by placing them in two rows of three so that each person in the first row is standing in front of someone in the second row. The heights of the people within each row must increase from left to right, and each person in the second row must be taller than the person standing in front of him or her. How many such arrangements of the 6 people are possible? A. 5 B. 6 C. 9 D. 24 E. 36 Key：A， 我选了C，想不明白为什么会选A
Q30: Joanna bought only $0.15 stamps and $0.29 stamps. How many $0.15 stamps did she buy? (1)
She bought $4.40 worth of stamps. (2)
She bought an equal number of $0.15 stamps and $0.29 stamps. A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient. B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient. C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient. D. EACH statement ALONE is sufficient. E. Statements (1) and (2) TOGETHER are NOT sufficient. Key：D 我选了A,为什么单独(2)也可以？想不通....
多谢！
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