Q100 / 180 · KCET 2014 · Mathematics
How many \( 5 \) digit telephone numbers can be constructed using the digits \( 0 \) to \( 9 \), if each
number starts with \( 67 \) and no digit appears more than once ?
number starts with \( 67 \) and no digit appears more than once ?
- Correct answerA\( 336 \)
- B\( 337 \)
- C\( 335 \)
- D\( 338 \)
Solution
3 digits from $0,1,2,3,4,5,8,9$
Arrangement of 8 digits taking 3 at a time is
8
$P_{3}=\frac{8 !}{5 !}$
$=8 \times 7 \times 6=42 \times 8=336$
Hence, the correct answer is option: 'A'.