Question

The numbers of numbers less than $2000$ that can be formed using the digits $1,2,3,4$ when repetition is allowed is

• A. $64$
• B. $148$
• C. $180$
• D. $1440$

Answer 1

The correct option is A $64$

The numbers is less than $2000$

$\therefore$ we can only keep 1 at thousand place.

$\therefore$ No. of ways $=4\times 4\times 4=64$