Question

The sum of the digits in the units place of all numbers formed with the help of 3, 4, 5 and 6 taken all at a time is

Answer 1

Step-by-step explanation:

total numbers formed will be 24 (if digits are not repeated)

let first 4 number be

3456

3465

3654

4653

sum of unit digits =18 (of these numbers)

since, total number of numbers formed is 24 , we take a group of 4 numbers at a time then ,6 times 6,5,4,3 will be at unit digit

therefore sum of all unit digit =18×6

=108.