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 7 of 11.

Narender reddy said:   10 years ago
I want to clear explanation prime no's and not prime no's.

Shilpa said:   10 years ago
1!+2!+.....50!/5!

= (1!+2!+......+50!) /1!+2!+.....+5!

= 6!+7!+....+50!

Shailendra kumar said:   10 years ago
After 4! all the no is divisible by 5! so answer is (1+2+6+24)/6 = 33/6 = 3 (rem).

Mahaboob basha said:   10 years ago
Hi friends I have a doubt please clear it.

What is the remainder when 1!+2!+3!+4!+5!+....+50! is divided by 5!?

Ramanna said:   1 decade ago
What is prime number?

Ramanna said:   1 decade ago
What is prime number?

Reshma said:   1 decade ago
Explain one example with 3 digit number?

Kavitha said:   1 decade ago
Please, give me detailed explanation about the prime number and solve the steps one by one in the problem.

Manju gouda said:   1 decade ago
Basically a number is prime no. If it has exactly 2 distinct factors. For e.g for 13 factors are 13 and 1. So it is a prime number. But for 1 factors are 1 only. So it is not a prime number.

Tinku das said:   1 decade ago
I want to know why 1 is not prime no?


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