Consider the following statements a. The number of ways to arrange the letters of the word ''PEPPER'' is 60.
Mathematics ·Previously asked in JKSSB Finance Account Assistant 2024
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Question
Consider the following statements:
a. The number of ways to arrange the letters of the word ''PEPPER'' is 60.
b. In a group of 20 people, the number of ways to select a committee of 3 members where the order doesn''t matter is C(20,3).
c. The expansion of (2 + x)^3 using binomial theorem is 8 + 6x + 12x² + x³.
d. The number of ways 3 boys and 3 girls sit in a row is 360.
Which of the following statement is correct?
- A. c and d
- B. b and c
- C. a and b (Correct answer)
- D. d and a
Correct Answer
Option C — a and b
Detailed Solution & Explanation
The correct answer is a and b.
Key Points
- a: PEPPER arrangements = 6!/(3!×2!×1!) = 720/12 = 60 ✓. b: C(20,3) for committee of 3 from 20 ✓. c: (2+x)³ = 8+12x+6x²+x³ (not 6x+12x²) ✗. d: 6 people in a row = 6!=720, not 360 ✗.
- Statements a and b are correct.
Additional Information
- Arrangements of a word with repeated letters use n! ÷ (p! q! …), dividing by the factorial of each repetition count.
- PEPPER has 6 letters with P three times and E twice, giving 6!/(3!·2!) = 60.
- Use permutations (ⁿPᵣ) when order matters and combinations (ⁿCᵣ) when it does not — a committee is a combination, a seating arrangement a permutation.
- The binomial expansion of (a + b)³ is a³ + 3a²b + 3ab² + b³, so (2 + x)³ = 8 + 12x + 6x² + x³.
Topics covered: Mathematics