单选题 Directions for Quantitative Comparison Questions: Some of the following questions give you two quantities, one in Column A and one in Column B, Compare the two quantities and choose one of the following answer choices:

A．if the quantity in Column A is greater;
B．if the quantity in column B is greater;
C．if the two quantities are equal;
D．if you cannot determine the relationship based on the given information

A
B
C
D

【正确答案】 A

【答案解析】To solve this problem, find maximum or minimum values for the percentages, given that 4＜a＜b＜5. The quantity 25% of a must be greater than i because it is given that 4＜a, and 25% of 4 is 1. The quantity 20% of b must be less than i because it is given that b＜5, and 20% of 5 is 1. Therefore the quantity in Column A is greater than the quantity in Column B.

A
B
C
D

【正确答案】 C

【答案解析】To solve this problem, convert the written English into mathematical symbols. If "x is two times y," then x=2y. Similarly, if y is [*] of z, then y=[*] To determine which quantity is greater, substitute [*] for y into x=2y to get [*]. Therefore, the quantities in Column A and B are equal.

A
B
C
D

【正确答案】 D

【答案解析】To solve this problem, simplify the quantity in Column A and compare it to Column B. It is given that r＞0, so the quantity [*]. However, you know only that r is greater than 0, so r could be less than, equal to, or greater than 2. Thus it is impossible to determine which quantity is greater based on the given information.