SIN练习题第6题
6.A teenager is downloading pirated, compressed songs in MP3 format from the Internet. Each song is about 3 minutes long when played, and needs about 2.9 megabytes of computer storage. To fill a CD requires about 70 minutes of music. If a 56K modem is being used which gives on average about 30 kilobits/sec of data flow, how many minutes does it take to download a full CD's worth of songs, ignoring setup times and filename entries? A byte represents 8 bits.
(A) 301 (B) 203 (C) 187 (D) 38 (E) 14
SIN练习题第6题答案解析
答案：A；解析如下：
With each song being 3 minutes long, there are 23.33 songs on a 70-minute CD. This requires a total storage of 2.9 megabytes x 23.33 = 67.67 megabytes. The modem processes about 30 kilobits/sec, which is 3.75 kilobytes/sec. At this rate, 67.67 megabytes will take (67.67x106)/(3750) = 18045 seconds or 301 minutes (A) or 5.01 hours!
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