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Aptitude · Q522

Number System

Competitive Exams · Aptitude · question 522

Q522

The sum of the digits of a natural number (10n - 1) is 4707, where n is a natural number. The value of n is :

A.
477
B.
523
Answer
C.
532
D.
704

Answer: Option B

Solution

Answer: Option B
Solution:
10n has (n + 1) digits, Then, 9 will appear n times in (10n - 1).
So, sum of digits in (10n - 1) = 9n
∴ 9n = 4707
⇒ n =  = 523