Permutations Combinations

  • Permutations-Combinations
  • 1. In how many different number of ways 4 boys and 2 girls can sit on a bench?

Answer: Option ''

Answer: Option 'C'
npn = n! 
6p6
= 6 × 5 × 4 × 3 × 2 × 1 = 720

  • 2. In how many different number of ways 5 men and 2 women can sit on a shopa which can accommodate persons? 

Answer: Option 'D'

Answer: Option 'D' 
7p3 = 7 × 6 × 5 = 210

  • 3. In how many different number of ways 4 boys and 3 girls can sit on a bench such that girls always sit together. 

Answer: Option 'A'

Answer: Option 'A'

  • 4. In how many different ways can the letters of the word "CLAIM" be rearrangement? 

Answer: Option 'A'

Answer: Option 'A' 
The total number of arrangements is 
5P5  = 5! = 120

  • 5. If the letters of the word PLACE are arranged taken all at a time, find how many do not start with AE. 

Answer: Option 'C'

Answer: Option 'C' 
Total no'of arrangements 5P5  = 5! = 120 
no'of arrangements start with AE = 1 × 6 = 6 
no'of arrangements which do not start with AE = 120 - 6 = 114.