Aptitude - Numbers - Discussion

Discussion Forum : Numbers - General Questions (Q.No. 1)
1.
Which one of the following is not a prime number?
31
61
71
91
Answer: Option
Explanation:
91 is divisible by 7. So, it is not a prime number.
Discussion:
108 comments Page 8 of 11.

Namrata said:   8 years ago
how to solve this question? Please tell me.

Rajesh said:   8 years ago
The Prime number means any number is divisible by one and itself.

Dilli Raja said:   8 years ago
For 3 numbers calculation:

Let us find whether 149 is prime or not.
[square root of 149= 12.20 < 13] prime numbers below 13 are 2,3,5,7,11.
149 is not exactly divisible by 2, because it don't has even number at the end.
149 is not exactly divisible by 3, because the sum of numbers 1+4+9= 14 is not divisible by 3.
149 is not exactly divisible by 5, because it don't has 0 or 5 at the end.
149 is not exactly divisible by 7,11.
So, 149 is a prime number.
(4)

Komal gupta said:   8 years ago
@Karthick.

I have not understood your process please explain me with the other examples.

Deekshi said:   8 years ago
Code for prime numbers below 100 is 442233322321.

2,3,5,7 (4)
11,13,17,19 (4)
23,29 (2)
31,37 (2)
41,43,47 (3)
53,59 (2)
61,67 (20
71,73,79 (3)
83,89 (2)
97 (1)

Prabhakar gupta said:   8 years ago
91is not a prime no. Because it is divisible by 13.

V ramesh said:   7 years ago
Prime number is nothing but it is divisible by one and itself that type of numbers called prime numbers.

Darshan said:   7 years ago
Thanks @Nidhin.

Annapurna said:   7 years ago
Thank you @Santosh.

Sharmi said:   7 years ago
Thank you @Dilipkumar.


Post your comments here:

Your comments will be displayed after verification.