NDA 2026
- Exam
- NDA
- Year
- 2026
- Subject
- Mathematics
- Chapter
- Permutation and Combination
NDA 2026 · Mathematics · Permutation and Combination
Passage: A 4-digit number is selected at random formed by using the...
Passage: A 4-digit number is selected at random formed by using the digits , , , and (where repetition of digits is not allowed).
Question: What is the probability that the number selected does not contain zero at any position ?
Question: What is the probability that the number selected does not contain zero at any position ?
Options
- A
- B
- C
- D
Correct answer
B.
Step-by-step solution
The total number of -digit numbers formed using the digits without repetition is calculated by filling the thousands place in ways (excluding ) and the remaining places in ^{4}P_{3}
The number of -digit numbers formed without using at any position means using only the digits .
Favorable outcomes = ^{4}P_{4} = 4 \times 3 \times 2 \times 1 = 24
Answer:
The number of -digit numbers formed without using at any position means using only the digits .
Favorable outcomes = ^{4}P_{4} = 4 \times 3 \times 2 \times 1 = 24
Answer: