Question

万维网在二十世纪九十年代刚流行时，下载速度最高约为每秒 $56$ 千比特。以这个速度下载一首 $4.2$ 兆字节的歌曲大约需要多少分钟？（注意一兆字节等于 $8000$ 千比特。）

When the World Wide Web first became popular in the 1990s, download speeds reached a maximum of about $56$ kilobits per second. Approximately how many minutes would the download of a $4.2$ -megabyte song have taken at that speed? (Note that there are $8000$ kilobits in a megabyte.)

$0.6$

$10$

$1800$

$7200$

$36000$

答案：B

知识点：单位换算速率

难度评级：960

解答：

歌曲大小为 $4.2\cdot8000=33{,}600$ 千比特。以每秒 $56$ 千比特下载，需要秒，即 $10$ 分钟。 $\frac{33{,}600}{56}=600$

正确答案是 B。

The song has $4.2\cdot8000=33{,}600$ kilobits. At $56$ kilobits per second, the download takes $\frac{33{,}600}{56}=600$ seconds, which is $10$ minutes.

Thus, the correct answer is B.

2022 AMC 8 第 7 题

答案：B

难度评级：960

解答：

其他年份的第 7 题