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:
105 comments Page 2 of 11.

Sindhuja B said:   4 years ago
The Question is "which is not a prime number".

In a very simple way how do we check whether a number is prime or not, .

The number should be divisible by one & the number it self right!.
Now see their options, that are, .

31. - is a prime number which can only be divided 1 & the number itself.
61. - same here.
71. - here too.
91. - is divisible by 1, 7, 91.

So, among other options, 91 is not a prime number.
(26)

Tharun said:   4 years ago
91 is correct because the prime number is one which is having two distinct factors so, that 91 having more than two factors.
(6)

Harika said:   4 years ago
31 is the prime number.

Pooja said:   5 years ago
n*n>=p in this form, how take that value by comparing p? Please explain anyone.

Swathi said:   5 years ago
Thanks all.

Jagadees said:   5 years ago
Thanks @Dilipkumar and @Santosh.

Sagarganeshkar said:   5 years ago
It is very easy by divisibility rules.

Jyoti said:   5 years ago
91 is the correct answer.

Kavitha said:   6 years ago
When we apply the condition.

n*n >=p for 91! How does that work?

(10*10>=91. Factors of 10 -2, 5, 10. So how is this condition satisfiying for the above question).?

Rameshwar said:   6 years ago
Thanks all.


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