The number of seven digit integer is to be formed using only 1, 2 &3 such that the sum of all the digits is 10 . so how many such seven digit number is possible ?
We start by listing the combinations of numbers that give us a digit sum of
We can have
#1, 1, 1, 1, 1, 3, 2#
And the number of different arrangements here is
Is the above sequence the only possible?
Note that you need a certain number of
#1, 1, 1, 1, 1, 1, 1, 3#
We either get sequences that are more or less than
Hopefully this helps!