Write five pairs of odd prime numbers less than 20 whose sum is divisible by 4
Answers
Concept
The definition of a prime number is a number with just two components, namely the number itself and the number 1. Take the number 5, for instance, which only has the elements 1 and 5. This indicates that the number is a prime. Using the number 6 as an example, which has more than two components (namely, 1, 2, 3, and 6), let's look at another case. The number 6 is therefore not a prime number.
Given
numbers that can be divided by 4 and are less than 20.
Find
we have to write five pairs of odd prime numbers which are less than 20 and whose sum is divisible by 4.
Solution
lets take the sum of the odd numbers which are divisible by 4.
1 ₊ 3 = 4
5 ₊ 3 = 8
7 ₊ 5 = 12
7 ₊ 9= 16
11 ₊ 1 = 12
Hence we get the five pairs of odd numbers less than 20 whose sum is divisible by 4 as (1,3)(5,3)(7,5)(7,9) and (11,1).
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Answer:
(3, 5), (3, 13), (3, 17), (5, 7) and (5, 11) are the pairs of odd prime numbers whose sum divisible by 4.
Step-by-step explanation:
List all the odd prime numbers less than 20.
There are 11 pairs of odd numbers less than 20 whose sum is divisible by 4.
Five such pairs are:
1) Sum of 3 and 5
3 + 5 = 8
Hence 8 is divisible by 4.
Therefore, 3 and 5 is the pair of odd prime numbers whose sum is divisible by 4.
2) Sum of 3 and 13
3 + 13 = 16
Hence 16 is divisible by 4.
Therefore, 3 and 13 is the pair of odd prime numbers whose sum is divisible by 4.
3) Sum of 3 and 17
3 + 17 = 20
Hence 20 is divisible by 4.
Therefore, 3 and 17 is the pair of odd prime numbers whose sum is divisible by 4.
4) Sum of 5 and 7
5 + 7 = 12
Hence 12 is divisible by 4.
Therefore, 5 and 7 is the pair of odd prime numbers whose sum is divisible by 4.
5) Sum of 5 and 11
5 + 11 = 16
Hence 16 is divisible by 4.
Therefore, 5 and 11 is the pair of odd prime numbers whose sum is divisible by 4.
Final answer: (3, 5), (3, 13), (3, 17), (5, 7) and (5, 11) are the pairs of odd prime numbers whose sum divisible by 4.
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