Difficulty: Easy
Correct Answer: 9334
Explanation:
Introduction / Context:
This is a letter-to-digit substitution coding question. Every letter of the alphabet that appears is assigned a unique digit. By comparing the given words and their codes, we can reconstruct the mapping and then apply it to a new word.
Given Data / Assumptions:
Concept / Approach:
We align letters with digits from each example to determine the letter–digit pairs. Once we know the digits for D, O and R, we can directly write the code for "DOOR" by substituting each letter with its corresponding digit, preserving order.
Step-by-Step Solution:
Step 1: Use TOAST → 03210.
T O A S T
0 3 2 1 0
So T → 0, O → 3, A → 2, S → 1.
Step 2: Use RIGID → 45759.
R I G I D
4 5 7 5 9
So R → 4, I → 5, G → 7, D → 9.
Step 3: Gather the digits needed for DOOR.
Word: D O O R.
We already know: D → 9, O → 3, R → 4.
Step 4: Substitute letter by letter.
D → 9, O → 3, O → 3, R → 4.
Thus DOOR → 9 3 3 4 → "9334".
Verification / Alternative check:
Check that the mapping is consistent: each letter always has the same digit wherever it appears. T, O, A, S, R, I, G, and D all have unique and stable codes across both example words, confirming that our mapping is correct.
Why Other Options Are Wrong:
"9331" uses 1 (which belongs to S) instead of 4 (which belongs to R). "3390" uses 0 (code for T) incorrectly. "1314" uses 1, 3, 1, 4, which does not match the letter sequence D O O R under any consistent substitution mapping.
Common Pitfalls:
Sometimes candidates try to find arithmetic relationships between digits, but for substitution ciphers, only the direct letter–digit pairing matters. Another error is to confuse which digit belongs to which repeated letter when reading the examples quickly.
Final Answer:
Using the same letter–digit code, "DOOR" is written as 9334.
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