HomeTestsSearchRankProfile
mediumMCQUPTET Paper 2 (Maths & Science)2017Mathematics and Science
1 mark

If a, a + 2, a + 4 are prime numbers, then the number of values of a is

  1. A
    one
  2. B
    two
  3. C
    three
  4. D
    more than three

Solution & Step-by-step Explanation

Let's examine the set of numbers where must be a natural number:Among any three consecutive odd numbers, exactly one must be a multiple of .For all three numbers to be prime simultaneously, the one that is a multiple of must equal itself (since is the only prime multiple of ).Let's test this condition:If : (Prime) (Prime) (Prime)This gives us the valid prime triplet .If we pick any other value for , one of the numbers in the triplet will be a composite multiple of (for example, if , the triplet is , where is composite).Thus, is the only valid solution, meaning there is exactly one possible value for .

Practice this question

Try it yourself before checking the explanation above.

If a, a + 2, a + 4 are prime numbers, then the number of values of a is
A
one
B
two
C
three
D
more than three

Share This Question

Related Questions

Ready for a Full Test?

Practice with timed mock tests and track your performance across Mathematics and Science.

Discussion