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How many prime number are there(i)less than 100, the difference in whose digits is...

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umaa | Student, Grade 9 | eNotes Newbie

Posted April 1, 2009 at 8:34 PM via web

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How many prime number are there
(i)less than 100, the difference in whose digits is 12?
(ii)which are divisible by 2?

2 Answers | Add Yours

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ahalperi | Middle School Teacher | (Level 1) Adjunct Educator

Posted February 15, 2013 at 4:03 AM (Answer #2)

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There are 13 pairs of prime numbers <100 that have a difference of 12:

5 and 17

7 and 19

11 and 23

17 and 29

19 and 31

29 and 41

31 and 43

41 and 53

47 and 59

59 and 71

61 and 73

67 and 79

71 and 83

 

2 is the only even prime by definition. Any other even number n (divisible by 2), is therefore not prime because it has 3 or more unique factors, including 1, 2, n

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deviselva75 | College Teacher | eNotes Newbie

Posted April 4, 2009 at 3:51 PM (Answer #1)

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there are 25 prime numbers are there in less than 100.

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97.

i)no of prime numbers in which   the difference in whose digit is 12:

13 prime numbers

ii) divisible by 2:

2. only one number is divisible by 2

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