Aptitude - Numbers - Discussion

Discussion Forum : Numbers - General Questions (Q.No. 9)
9.
Which of the following is a prime number ?
33
81
93
97
Answer: Option
Explanation:
Clearly, 97 is a prime number.
Discussion:
47 comments Page 1 of 5.

ARUN said:   2 weeks ago
An easy way to find a number is prime or not.

Divide the number by 6 and check whether the reminder is +1 or -1. Then the number is a prime number.
formula : 6(x)(+-)plus or minus 1 .

Example:
97 is prime or not.

97/6=6(16)+1=>96+1=97 it is prime number. //ends with +1 or -1

41 is prime or not.
41/6=6(8)-1=> 42-1=41 it is prime number //ends with +1 or -1

Naina Bhardwaj said:   3 years ago
Good explanation,Thanks @Viki.
(2)

Subhankar Banik said:   3 years ago
Good Explanation! Thanks all.
(1)

Ganesh Barik said:   3 years ago
Thanks all for explaining the answer clearly.
(1)

Rishi said:   4 years ago
97 is the answer because we can't divide this number with any prime number.
(3)

Abdulmajid Ma'aji katsina said:   4 years ago
Thanks all for explaining it.
(1)

Yogesh said:   4 years ago
No, it's divided by 7 it is not a prime number.
(4)

Vidya kharvi said:   4 years ago
Yes, 97 is a prime number.

Because as per prime num definition i.e prime number is a number that is divisible by 1 and itself. 33 is not a prime num because it is divisible by 3, 81 is also not a prime num because it is divisible by 9, 93 is also not a prime num because it is divisible by 3 but whereas 97 is not divisible by any other num expect 1 and itself so, 97 is a prime number.
(19)

Paimon Dkhar said:   7 years ago
97 is a prime Number.
(1)

Siddharth daggubati said:   7 years ago
Yes, 97 is the prime number.
(2)


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