UPSC Civil Services 2020 Prelims General Studies Paper II

Given, the sum of digits =10n+1
∴‌‌ Number =10n+1
When, n=0
∴‌‌ Number =100+1=1+1=2
When, n=1 ∴ Number =101+1=10+1=11( Sum is 2)
When, n=2 ∴ Number =102+1=100+1=101( Sum is 2)
When, n=3 ∴ Number =103+1=1000+1=1001( Sum is 2)
Here, sum of digits of number will always be 2 when n=0,1,2,3,...
Hence, the sum of digits in the number is 2 for any whole number n.