# Aptitude - Numbers - Discussion

Discussion Forum : Numbers - General Questions (Q.No. 1)

1.

Which one of the following is not a prime number?

Answer: Option

Explanation:

91 is divisible by 7. So, it is not a prime number.

Discussion:

101 comments Page 1 of 11.
Vishala said:
2 months ago

Thank you all for explaining the answer.

(2)

Nishu said:
4 months ago

@All.

Thank You so much, it was very helpful to me.

Thank You so much, it was very helpful to me.

(2)

Jaanu Jaanu said:
9 months ago

Thanks both of you for the clear explanations. @Hafiz and@ Dilip.

(2)

Monisha Mohanan said:
2 years ago

@All.

Prime number means that a number that is divisible only by itself and 1

Examples : 2,3,5,7,11.

Now in our question the options s 31, 61,71 and 91 here I think in our example we can find that the prime numbers only start with 2,1,3,5,7.

Thus the answer becomes 91.

Prime number means that a number that is divisible only by itself and 1

Examples : 2,3,5,7,11.

Now in our question the options s 31, 61,71 and 91 here I think in our example we can find that the prime numbers only start with 2,1,3,5,7.

Thus the answer becomes 91.

(4)

Jitu said:
2 years ago

Why only 91 is not a prime number?

In this case, 71 is also divisible by 3.

In this case, 71 is also divisible by 3.

(2)

Sharma said:
2 years ago

91 prime or not.

Which square number is exceeds 91?

10 ^2 right. So let's take a prime number which is less than 10.

2, 3, 5, 7.

Check the given number is divisible by 2, 3, 5, 7.

If it is divisible then it is not a prime number.

If not that would be a prime number.

Which square number is exceeds 91?

10 ^2 right. So let's take a prime number which is less than 10.

2, 3, 5, 7.

Check the given number is divisible by 2, 3, 5, 7.

If it is divisible then it is not a prime number.

If not that would be a prime number.

Sindhuja B said:
2 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.

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.

(2)

Tharun said:
2 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.

Harika said:
2 years ago

31 is the prime number.

Pooja said:
2 years ago

n*n>=p in this form, how take that value by comparing p? Please explain anyone.

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