In a certain code language, ‘TEND’ is coded as ‘1876’ and ‘NOTE’ is coded as…
2025
In a certain code language, ‘TEND’ is coded as ‘1876’ and ‘NOTE’ is coded as ‘6789’. What is the code for ‘O’ in that language?
Answer: B. 9 — Concept: When two coded words share letters, compare the SETS of digits used in each code rather than reading them position by position. Digits common to both…
- A.
8
- B.
9
- C.
6
- D.
7
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Show answer & explanation
Correct answer: B
Concept: When two coded words share letters, compare the SETS of digits used in each code rather than reading them position by position. Digits common to both codes must represent the letters common to both words; a digit appearing in only one word's code must represent that word's one letter that is absent from the other word.
TEND's coded digits are {1, 8, 7, 6}; NOTE's coded digits are {6, 7, 8, 9}.
TEND and NOTE share the letters T, E and N (three letters); the two digit sets share exactly three digits, {6, 7, 8}, so between them these three digits represent T, E and N.
The one letter in TEND that is absent from NOTE is D; the one digit in TEND's code that is absent from NOTE's code is 1. So D's code is 1.
The one letter in NOTE that is absent from TEND is O; the one digit in NOTE's code that is absent from TEND's code is 9. So O's code is 9.
Cross-check: Reading NOTE position by position (N-O-T-E matched to 6-7-8-9) would suggest O = 7, but the same position-by-position reading of TEND gives T = 1 and E = 8, while NOTE's own reading gives T = 8 and E = 9 — two different codes for the same letters. This contradiction shows the codes are not fixed by letter position at all; only the set-matching method above is consistent with both clues, and it uniquely fixes O = 9.
Answer: The code for O is 9.