Challenge

Siddhant chaudhary

When the numbers from 1 to n are written in decimal notation . It is found that the no. Of digits in writting all these is 1998. Find n? First three correct answers are declared real iitjee aspirant. So hurry up

Vishal U. Karve

No. of digits used for

(1-9)=9

(10-99)= 2*90 = 180

(100-n) = 3*(n-100+1) = 3n - 297

Total digits used = 9+180+3n-297

=3n-108

3n-108=1998

Therefore n=702

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