Permutations & Combinations · NDA previous year questions

2023 3 questions

1. Q92023 · 16 Apr 2023

   Let AX = B be a system of 3 linear equations with 3-unknowns. Let X  and X  be its two distinct solutions. If the combination aX  + bX  is a solution of AX = B; where a, b are real numbers, then which one of the following is correct ?

   1. A.a = b
   2. B.a + b = 1
   3. C.a + b = 0
   4. D.a - b = 1
   Show answer

   Answer: B

2. Q292023 · 16 Apr 2023

   Let x be the number of permutations of the word ‘PERMUTATIONS’ and y be the number of permutations of the word ‘COMBINATIONS’. Which one of the following is correct ?

   1. A.x = y
   2. B.y = 2x
   3. C.x = 4y
   4. D.y = 4x
   Show answer

   Answer: C

3. Q302023 · 16 Apr 2023

   5-digit numbers are formed using the digits 0, 1, 2, 4, 5 without repetition. What is the percentage of numbers which are greater than 50,000 ?

   1. A.20%
   2. B.25%
   3. C.$\frac{100}{3}\%$
   4. D.$\frac{110}{3}\%$
   Show answer

   Answer: B