Out of 7 consonants and 4 vowels, how many 5-letter words consisting of 3 consonants and 2 vowels can be formed?
Aptitude
Permutation and Combination
Difficulty: Medium
Choose an option
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A25200
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B12600
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C5040
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D4200
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ENone of these
Answer
Correct Answer: 25200
Explanation
Problem restatementChoose 3 consonants and 2 vowels and arrange the 5 chosen letters in all possible orders.
Given data
- Consonants available = 7.
- Vowels available = 4.
- Word length = 5 (with 3 consonants + 2 vowels).
Concept/ApproachIndependent selection followed by permutations: choose letters first, then arrange them (all distinct).
Step-by-step calculation Choose consonants: C(7, 3) = 35 Choose vowels: C(4, 2) = 6 Arrange 5 letters: 5! = 120 Total = 35 × 6 × 120 = 25200
Verification/AlternativeThe multiplication principle applies: selections are independent and letters are distinct.
Common pitfalls
- Multiplying by 5! before selecting the letters, or double-counting arrangements.
Final Answer25200