Permutation and Combinations — Maths STD 11 Science — Question
CBSE BoardEnglish MediumSTD 11 ScienceMathsPermutation and Combinations1 Mark
MCQ
The number of nine digit numbers that can be formed with different digits is:
A
$9.8!$
B
$8.9!$
✓
$9.9!$
D
$10!$
✓
Answer
Correct option: C.
$9.9!$
The first digit is one of $(1, 2, 3, 4, 5, 6, 7, 8, 9) ($i.e., all expect $0).$
So, the no of ways $=9$
The remaining $8$ digits are to be taken from the remaining $9$ numbers.
So, the no of ways $= \ ^9\text{P}_8$
So, total no. of ways $=9\times\ ^9\text{P}_8$
$=9\times9!$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.