MCQ
The number $111..............1$ ($91$ times) is a
- AEven number
- BPrime number
- ✓Not prime
- DNone of these
$ = \frac{{1.({{10}^{91}} - 1)}}{{10 - 1}} = \frac{{{{({{10}^{13}})}^7} - 1}}{{{{10}^{13}} - 1}} \times \frac{{{{10}^{13}} - 1}}{{10 - 1}}$
$ = [{({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.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.