Question:
The sum of all the 4-digit distinct numbers that can be formed with the digits $1,2,2$ and 3 is:
Correct Option: 1
Solution:
Digits are $1,2,2,3$
total distinct numbers $\frac{4 !}{2 !}=12$.
total numbers when 1 at unit place is 3 .
2 at unit place is 6
3 at unit place is 3 .
So, sum $=(3+12+9)\left(10^{3}+10^{2}+10+1\right)$
$=(1111) \times 24$
$=26664$