A CD has 12 music tracks of lengths (in minutes) 3, 7, 4, 3, 5, 6, 4, 5, 4, 7, 8, 8, and each minute of music requires 12 MB of storage. Which statement is correct?

A512 MB of memory is used for the 12 tracks.

B1 GB of memory is used for the 12 tracks.

C768 MB of memory is used for the 12 tracks. ✓ Correct

DIf stored as MP3, each track shrinks by 90%, so 12 tracks need 69.12 MB.

Correct answer: (C) 768 MB of memory is used for the 12 tracks.

Explanation

The twelve tracks total 64 minutes, and at 12 MB per minute that needs 768 MB of storage.

The claim of 512 MB understates the total, which is actually 768 MB.

The claim of 1 GB overstates the requirement, since 768 MB is well below 1024 MB.

The MP3 figure of 69.12 MB does not follow from a 90 percent reduction of 768 MB, which would leave 76.8 MB.

Adding the track lengths 3, 7, 4, 3, 5, 6, 4, 5, 4, 7, 8, 8 gives 64 minutes.

Storage need equals total playing time multiplied by the size per minute.

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