Permutation and Combination Questions

Multiple choice
  1. 15220

  2. 15120

  3. 15140

  4. 15620

  5. 2160

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

KABRISTAN has 9 letters with vowels A, I, A (3 vowels). Treat the 3 vowels as one unit. We have 7 items to arrange (K,B,R,S,T,N and the vowel unit). These can be arranged in 7! ways. The 3 vowels within their unit can be arranged in 3!/2! ways (since A repeats twice). Total = 7! × (3!/2!) = 5040 × 3 = 15120. Option B is correct. This uses the permutation formula for arranging items with some items grouped together.

Multiple choice
  1. 600

  2. 601

  3. 610

  4. Can't be determined

  5. None of these

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Letters in SACHIN in alphabetical order: A, C, H, I, N, S. Words starting with A, C, H, I, N each give 5! = 120 arrangements, totaling 600. For words starting with SA: second letter position in ACHIN gives: SAB... (24), SAC... (24), SAH... (24), SAI... (24), SAN... (24), then SACHIN. Total: 600 + 120 = 601.

Multiple choice
  1. 6720

  2. 6840

  3. 2520

  4. 5040

  5. 5820

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The word DIMINISH has 8 letters with the letter I repeated 3 times. When arranging letters with repetitions, we divide the total factorial by the factorial of repeated letters: 8!/3! = 40320/6 = 6720. Option D (5040) would be the answer if all letters were unique (8! = 40320 is incorrect).

Multiple choice
  1. 5040

  2. 2520

  3. 1260

  4. 1020

  5. 720

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The word ALGEBRA has 7 letters, but the letter A is repeated twice. The number of distinct arrangements is 7!/2! = 5040/2 = 2520. Option A (5040) is incorrect because it doesn't account for the repetition. Option C (1260) would be 7!/4!, which is not the case here.

Multiple choice
  1. 25

  2. 36

  3. 720

  4. 360

  5. 1040

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The word 'CREATE' has 6 letters, with 'E' appearing twice. Formula: 6! / 2! = 720 / 2 = 360. When arranging letters of a word with repeated letters, divide the factorial of total letters by the factorial of the count of each repeated letter. This accounts for identical arrangements caused by repeated letters.