Question

What should the "check digit" be for the following credit card number: 5326 8503 0124 460_?

A) 1
B) 2
C) 3
D) 4

Answer 1

The check digit for the given credit card number is 3.

Step-by-step explanation:

The check digit for the given credit card number can be calculated using the Luhn algorithm. The Luhn algorithm is a mathematical formula used to validate credit card numbers. Here is how the algorithm works:

1. Starting from the rightmost digit, double every second digit. In this case, the number becomes 5 6 2 6 1 0 4 0 0 2 2 9 4 0 _.
2. If the doubled digit is greater than 9, add the digits of the result. For example, the doubled digit 12 becomes 1 + 2 = 3.
3. Sum up all the digits. In this case, the sum is 5 + 6 + 2 + 6 + 1 + 3 + 4 + 0 + 0 + 2 + 2 + 9 + 4 + 0 + 3 = 47.
4. Find the digit that needs to be added to the sum (check digit) to make it a multiple of 10. In this case, the check digit is 3, because 47 + 3 = 50, which is a multiple of 10.

Therefore, the check digit for the given credit card number is C) 3.