Co-Prime and Twin Prime Numbers


 
 
Concept Explanation
 

Co-Prime and Twin Prime Numbers

Prime Numbers: A number which has only two different factors, 1 and the number itself is called prime number. e.g. 2, 3, 5, 7

Co-Prime Numbers: Two numbers are said to be co-prime when they have only 1 as common factor.e.g. 3 and 5: 19 and 20

Twin Prime Numbers: Two prime numbers whose difference is 2 are called are called Twin Prime Numbers. e.g. 3 and 5: 41 and 43.

Illustration: State whether the following numbers are co-prime or not.

(i) 4 and 17

(ii) 25 and 15

(iii) 13 and 19

(iv) 56 and 12

Solution: (i) As 4 and 17 have only 1 as common factor. Hence 4 and 17 are co-prime numbers.

(ii) As 25 and 15 have common factors as 5,1 . Hence 25 and 15 are not co-prime numbers.

(iii) As 13 and 19 have only 1 as common factor. Hence 13 and 19 are co-prime numbers.

(iv) As 56 and 12 have common factors as 2, 4,1. Hence 56, 12 are not co-prime numbers.

Illustration: How many twin prime numbers are there in between 90 and 100?

Solution: There are no Twin Prime Numbers between 90 and 100.

Sample Questions
(More Questions for each concept available in Login)
Question : 1

Which of the following pairs are co-prime?

Right Option : D
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Explanation
Question : 2

Choose the co-prime numbers from the following pairs.

Right Option : B
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Explanation
Question : 3

Consider the following statement :

i. The product of two composite numbers remains same on changing their order.

ii. The product of a pair of co-primes is changed on changing their order.

Right Option : C
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Explanation
 
 
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