AMC 8 1986 Problem 5
AMC8 1986 年第 5 题
表达式与运算★★☆☆☆
A contest began at noon one day and ended 1000 minutes later. At what time did the contest end?
某竞赛于一天中午开始，1000 分钟后结束。竞赛在什么时间结束？
- A.
- B. / 午夜
- C.
- D.
- E.
正确答案 · Correct Answer
D
解析 · Solution
Solution 1
The contest lasts 1000 minutes, which is = 16 hours or 16 hours and 40 minutes. Since the contest starts at , it ends at
There are 60 minutes in an hour. So, we can easily eliminate some of the choices by noting that noon is exactly 720 minutes away from midnight. Since 720 < 1000, we know that it cannot be A or B. Because midnight is 720 minutes away, we know that the contest ended 1000 - 720 = 280 minutes after midnight. The highest multiple of 60 that will fit into 280 is 240, which is 4×60, and the remainder is 40 minutes, meaning that the contest ended at is
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