Published by:
CGP EDU Academic Team
Published on: August 11, 2026
The number 111.....1 (91 times) is a -
Text Solution
Verified by ExpertsThe correct answer is:
C
Let S = 1 + 10 + 10 2 + ….+10 90
= 
= 
× 
= [(10 13 ) 6 + (10 13 ) 5 + (10 13 ) 4 +….+1] × (10 12 + 10 11 +….+1)
∴ It is the product of two integers and hence not prime.
Prepare Smarter with CGP Edu
Get practice questions, solutions, and test series in one place.
Write a Review
Share your experience with this question and solution.
Commentary
Send your comment, doubt, correction, or feedback to admin.
Similar Questions
Explore conceptually related problems
For 0 < θ θ < π π /2, if x =
then
If a, b and c are distinct positive real numbers and a 2 +b 2 +c 2 =1, then ab + bc +ca is
If the product of n positive numbers is unity , then their sum is
If a, b and c are positive real numbers, then the least value of (a + b + c) is
If a, b and c are positive real numbers then is greater than or equal to
If the first and the (2n-1)th terms of an A.P., G.P. and H.P. are equal and their nth terms are a, …