Question

How many 7 digit numbers can be created from numbers 1,2 and 3, in which the sum of digits of the number is equal to 10? 1,2and3 can be repeated. plzz tell it's answer stepwise

Answer 1

1+2+3+3+1=10
now we got 10 now subtracted it by 3
10-3=7

Answer 2

For each combination of numbers, there is 3^7 = 2187 different possible order of numbers.

1 three 1 two and 5 ones

3 twos 4 ones

2187 x 2 = 4374 different choices