The ache of number
Probability
Level
pending
The sum of all distinct four digit number that can be formed using the 1,2,3,4 and 5, each digit appearing at most once, is
The answer is 399960.
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
1 solution
There are 5 ∗ 4 ∗ 3 ∗ 2 = 1 2 0 distinct 4 digit numbers to add. The numbers 1 through 5 will be evenly distributed regarding the 4 positions, so each of these numbers will appear in the k th position 5 1 2 0 = 2 4 times, where 1 ≤ k ≤ 4 . Thus the sum will be
2 4 ∗ ( 1 + 2 + 3 + 4 + 5 ) ∗ ( 1 0 0 0 + 1 0 0 + 1 0 + 1 ) = 3 9 9 9 6 0 .