AMC 8 2007 Problem 6
AMC8 2007 年第 6 题
百分比★★☆☆☆
The average cost of a long-distance call in the USA in 1985 was 41 cents per minute, and the average cost of a long-distance call in the USA in 2005 was 7 cents per minute. Find the approximate percent decrease in the cost per minute of a long- distance call.
1985 年在美国打长途电话的平均费用是每分钟 41 美分，2005 年在美国打长途电话的平均费用是每分钟 7 美分。求长途电话每分钟费用减少的大致百分比。
- A.7
- B.17
- C.34
- D.41
- E.80
正确答案 · Correct Answer
E
解析 · Solution
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