Suppose the fourth digit of the Postnet code 282x4-2486-3 is obscured. What is the missing digit?
A) 1
B) 3
C) 7
D) The missing digit can't be determined.

Question

Quizplus · Accepted Answer

The Postnet code uses a check digit calculation to ensure accuracy. The sum of all the digits, including the check digit (the last digit), must be a multiple of 10. In this case, adding the visible digits 2+8+2+x+4+2+4+8+6+3 = 39+x. For the total to be a multiple of 10, x must be 1, making the sum 40.

Suppose the Fourth Digit of the Postnet Code 282x4-2486-3 Is