AMC8 1992

AMC8 1992 · Q21

AMC8 1992 · Q21. It mainly tests Percent, Arithmetic misc.

Northside's Drum and Bugle Corps raised money for a trip. The drummers and bugle players kept separate sales records. According to the double bar graph, in what month did one group's sale exceed the other's by the greatest percent?

Northside的鼓乐队为旅行筹集资金。鼓手和小号手保持单独的销售记录。根据双柱状图，在哪个月一个小组的销售额超过另一个小组的百分比最大？

(A) Jan 一月

(B) Feb 二月

(D) Apr 四月

(E) May 五月

Answer

Correct choice: (B)

正确答案：（B）

Solution

Answer (B): Compute the ratios for each month: \[ \begin{array}{lccccc} \text{Month} & \text{Drums} & \text{Bugles} & \text{Diff.} & \text{Diff.:Lower} & \% \text{ exc.} \\ \text{Jan:} & 7 & 9 & 2 & 2\!:\!9 & 29\% \\ \text{Feb:} & 5 & 3 & 2 & 2\!:\!3 & 67\% \\ \text{Mar:} & 9 & 6 & 3 & 3\!:\!6 & 50\% \\ \text{Apr:} & 9 & 12 & 3 & 3\!:\!9 & 33\% \\ \text{May:} & 8 & 10 & 2 & 2\!:\!8 & 25\% \\ \end{array} \] Thus the percent is greatest in February. Note. Students can estimate the required ratio by visually comparing the difference between the columns to the shorter column.

答案（B）：计算每个月的比率： \[ \begin{array}{lccccc} \text{月份} & \text{鼓} & \text{号} & \text{差} & \text{差:较小者} & \text{超出百分比} \\ \text{一月:} & 7 & 9 & 2 & 2\!:\!9 & 29\% \\ \text{二月:} & 5 & 3 & 2 & 2\!:\!3 & 67\% \\ \text{三月:} & 9 & 6 & 3 & 3\!:\!6 & 50\% \\ \text{四月:} & 9 & 12 & 3 & 3\!:\!9 & 33\% \\ \text{五月:} & 8 & 10 & 2 & 2\!:\!8 & 25\% \\ \end{array} \] 因此，百分比在二月最大。注：学生可以通过目测比较两列之间的差与较短一列的大小，来估计所需的比率。

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