Arranging the letters of LEADER — Aptitude Question
Arranging the letters of LEADER: In how many ways can the letters of the word LEADER be arranged? Answer and worked solution on CodeKairo.
- Topic: Permutations & Combinations
- Section: Quantitative Aptitude
- Difficulty: Medium
- Time target: 60 seconds
Question
In how many ways can the letters of the word LEADER be arranged?
Options
- 120
- 240
- 360
- 720
Show the answer and the worked solution
Correct answer: C. 360
Worked solution
- LEADER has 6 letters: L, E, A, D, E, R — with E appearing twice.
- Arrangements = 6!/2! = 720/2 = 360.
Answer: 360.
The idea
Divide n! by the factorial of each repeat count. Ignoring the repeated E gives 720, which is offered.
Shortcut. Place the two E's first: choose their positions in C(6,2) = 15 ways, then arrange L, A, D, R in the other four in 4! = 24 ways. 15 × 24 = 360.
Common trap. "720" — computing 6! as if the two E's were different letters; swapping them gives the same word, so every arrangement is counted twice.
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