Books Are Assigned Identification Numbers Called ISBNs $0 - 673 - 99893 - 2$

question 49

Multiple Choice

Books are assigned identification numbers called ISBNs. Each ISBN is a ten-digit number such as $0 - 673 - 99893 - 2$ . The final digit is called the check digit which is determined on the basis of modular arithmetic. The final (check) digit is obtained as follows: start at the left and multiply the first nine digits of the ISBN number by $10,9,8,7,6,5,4,3$ , and 2 respectively. Then add these products. The check digit is the smallest number that must be added to the result to get a multiple of 11 .
Find the check digit for the ISBN 0-681-81927-__.

• A) 1
• B) 7
• C) 8
• D) 4

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Definitions:

NREM Rebound

The increase in the amount of non-rapid eye movement (NREM) sleep after being deprived of sleep, as a compensatory response.

Sleep Apnea

A sleep disorder characterized by pauses in breathing or shallow breaths during sleep, leading to poor sleep quality and other health issues.

Delta Waves

High amplitude brain waves of a frequency between 1-4 hertz, typically associated with deep sleep.

Stage 3 Sleep

A deep sleep phase within the sleep cycle characterized by delta brain waves, important for physical recovery and growth.