Suppose the first digit of the ISBN x-7127-1011-0 is obscured. What is the missing digit?
A) 5
B) 6
C) 9
D) 0

Name: Suppose the first digit of the ISBN x-7127-1011-0 is obscured. What is the missing digit? A) 5 B) 6 C) 9 D) 0
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Question

Quizplus · Accepted Answer

The ISBN-10 check digit is calculated by multiplying each digit by its position (1 to 10) and summing the results. The sum must be divisible by 11. For x-7127-1011-0, the sum is 1*x + 2*7 + 3*1 + 4*2 + 5*7 + 6*1 + 7*0 + 8*1 + 9*1 + 10*0. Solving for x gives x = 5.

Suppose the First Digit of the ISBN X-7127-1011-0 Is Obscured