Aptitude - Numbers - Discussion
Discussion Forum : Numbers - General Questions (Q.No. 12)
12.
The sum of first five prime numbers is:
Answer: Option
Explanation:
Required sum = (2 + 3 + 5 + 7 + 11) = 28.
Note: 1 is not a prime number.
Definition: A prime number (or a prime) is a natural number that has exactly two distinct natural number divisors: 1 and itself.
Discussion:
29 comments Page 3 of 3.
Gouthami said:
8 years ago
There is any formula for this?
Greeshmitha pillalamarri said:
8 years ago
The first five prime numbers are 2, 3, 5, 7, 11 and we know that prime numbers start from 2. Now, the sum of first five prime numbers is 2+3+5+7+11=28 so it is clear that sum of first five prime numbers are 28. Thank you!
(1)
Babu said:
8 years ago
Why 1 is not a prime number? It also divided by 1 and itself. It's my doubt please clear it.
Fairu said:
8 years ago
Please tell me how to find the sum of first 100 prime numbers.
Any formula is there for that?
Any formula is there for that?
(2)
Megnah said:
7 years ago
@All.
I have one simplest method to find the sum of first n natural no's by using the formula n(n+1)/2.
For eg:
To find the sum of first 50 natural no's,
(NOTE:always natural no starts with 1),
Where n=50.
Then 50(50+1)/2 =>50(51)/2 =>2550/2.
=>1275.
Ans: The sum of the first 50 number is 1275.
I have one simplest method to find the sum of first n natural no's by using the formula n(n+1)/2.
For eg:
To find the sum of first 50 natural no's,
(NOTE:always natural no starts with 1),
Where n=50.
Then 50(50+1)/2 =>50(51)/2 =>2550/2.
=>1275.
Ans: The sum of the first 50 number is 1275.
(1)
Sakib said:
6 years ago
@Megnah, this formula doesn't apply for the first five numbers.
n(n+1)/2=15.
n(n+1)/2=15.
(3)
Pranjal Bajpai said:
5 years ago
@Babu.
1 is not prime as we don't have the choice to check it's divisibility other than itself.
1 is not prime as we don't have the choice to check it's divisibility other than itself.
Sajjad said:
4 years ago
2+3+5+7+11=28,
1 is not a prime number because the prime number has only 2 different factors, 1 has only one factor therefore it is not a prime number.
1 is not a prime number because the prime number has only 2 different factors, 1 has only one factor therefore it is not a prime number.
(1)
Suresh said:
3 years ago
2 + 3 + 5 + 7 + 11 = 28.
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