SOLUTION: NO.1.How many number are there which consist of seven figures(digits)? NO.2How many numbers not more than fours digits can be formed with 7,8,9? I need these answers,today.Pl

Algebra ->  Permutations -> SOLUTION: NO.1.How many number are there which consist of seven figures(digits)? NO.2How many numbers not more than fours digits can be formed with 7,8,9? I need these answers,today.Pl      Log On


   

Question 98302: NO.1.How many number are there which consist of seven figures(digits)?
NO.2How many numbers not more than fours digits can be formed with 7,8,9?
I need these answers,today.Please help me....

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
1) 9999999-999999=9000000 ... largest 7 digit minus largest 6 digit

2) 3+3^2+3^3+3^4=120 ... 1 digit+2 digit+3 digit+4 digit ... each digit has 3 possibilities