Question

The number of $5$-digit telephone numbers that can be constructed using the digits from $0$ to $9$, if every number starts with $67$ and no digit appears twice is

• A. 336.0
• B. 336.00
• C. 336

Answer 1

Answer: (A), (B), (C)

Let the number be of form $67\_\_\_$
As the repetition is not allowed, the digits available are $0,1,2,3,4,5,8,9$
$\therefore$ The required number of $5$-digit numbers
$=8\times 7\times 6=336$