QJEEM23Ma0b31: JEE Main 2023 Mathematics - Class 11 JEEM23Ma0b31 Solution: The sum of all the four-digit numbers that can be formed using…

We have, four digits are $2,1,2,3$ .

Total numbers when 1 is at unit digit $=\frac{3 !}{2 !}=3$

Total number when 2 is at unit digit $=3 !=6$

Total numbers when 3 is at unit digit $=\frac{3 !}{2 !}=3$

Sum of digits at unit place $=3 \times 1+6 \times 2+3 \times 3=24$

$\therefore$ Required sum $=24 \times 1000+24 \times 100+24 \times 10+24 \times 1$

$=24 \times 1111=26664$