How many letters retain their original positions when the letters of the word…
2026
How many letters retain their original positions when the letters of the word THURSDAY are arranged in English alphabetical order?
Answer: C. Three — ConceptTo count unchanged positions after rearrangement, write the original sequence and the rearranged sequence in aligned positions. Compare the letters…
- A.
One
- B.
Zero
- C.
Three
- D.
Two
Attempted by 28 students.
Show answer & explanation
Correct answer: C
Concept
To count unchanged positions after rearrangement, write the original sequence and the rearranged sequence in aligned positions.
Compare the letters position by position; count an index only when the letter at that index is identical in both sequences.
Application
The original sequence is THURSDAY. Its letters in alphabetical order are ADHRSTUY.
Position | Original letter | Alphabetical-order letter | Comparison |
|---|---|---|---|
1 | T | A | Changed |
2 | H | D | Changed |
3 | U | H | Changed |
4 | R | R | Unchanged |
5 | S | S | Unchanged |
6 | D | T | Changed |
7 | A | U | Changed |
8 | Y | Y | Unchanged |
Cross-check
Positions 1, 2, 3, 6, and 7 change, giving five changed positions.
Positions 4, 5, and 8 remain unchanged, giving three unchanged positions.
The counts add to 5 + 3 = 8, which equals the total number of letters.
Result
Therefore, three letters retain their original positions.