Question

The sum of the digit of a number 10^n -1 is 3798 find value of n



It is correct
Plz answer step by step and no meaningless answers

Answer 1

Given sum of 10n-1=3798

by this we can find first term 10n-1 put n=1 we get 9

second term put n=2 we get 19

a=9

d=second term-first term

d=10

Sn=3798

by AP we have Sn=[2a+(n-1)d]

3798=[2*9+(n-1)10]

3798=[18+10n-10]

3798=[8+10n]

n=379