Question 220 of 278MediumMCQ
The sum of the digits in the unit's place of all the 4-digit numbers formed by using the numbers 3, 4, 5 and 6, without repetition, is:
Solutions · 1
Official solution
For each fixed unit digit, the remaining 3 digits arrange in 3!=6 ways.
\[\text{Sum} = 6(3+4+5+6) = 6\times18 = 108\] Answer the question to unlock