ITPEC FE Subject A April 2026 Question 18

73940 — the check digit works out to 0, appended to the original 7394.

Apply the three steps to data 7394 with weight 1234 and base 11:

1. Weighted sum: 7×1 + 3×2 + 9×3 + 4×4 = 7 + 6 + 27 + 16 = 56
2. Remainder: 56 mod 11 = 1
3. 11 − 1 = 10, and the last digit of 10 is 0

Appending gives 73940.

Answer (a)

Why not others:
- (b) 73941 — uses the remainder 1 directly as the check digit, skipping step 3
- (d) 73947 — applies the weight in reverse order (4321), giving a sum of 59, remainder 4 and check digit 7
- (c) 73944 — the same reversed weighting, then stops at the remainder 4 without doing step 3

Key rule: Align the weight with the data left to right, and do not stop at the remainder — the check digit is the last digit of base minus remainder, which is why a remainder of 0 yields a check digit of 1, not 11.

AI-generated — may contain errors