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the sum of angie's age and john's age equals michael's age. angie's age is a prime number, but john's age and michael's age are not prime numbers. the sum of john's age and michael's age is a prime number, and angie's age minus john's age is a prime number. one more than half of john's age is a prime number. angie is the only teenager, and she is older than john. how many years old is john?

User Johnna
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1 Answer

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Final answer:

After assessing the conditions and applying them, it is determined that John is 8 years old. Angie's age as a teenager must be a prime number, which leaves us with the options of 13, 17, or 19. John's age must satisfy the condition that one more than half his age is a prime number, eliminating all options but 8 for his age.

Step-by-step explanation:

We need to find John's age based on the given conditions:

  1. Angie's age + John's age = Michael's age
  2. Angie's age is a prime number
  3. John's age and Michael's age are not prime numbers
  4. John's age + Michael's age = prime number
  5. Angie's age - John's age = prime number
  6. 1 more than half of John's age is a prime number
  7. Angie is a teenager older than John

Let's take into account the age constraints:

  • Since Angie is the only teenager and older than John, her age could be any prime number between 13 and 19: 13, 17, or 19.
  • Since 1 more than half of John's age is prime, and knowing that he is younger than a teenager, possible ages for John are ages that result in prime numbers when halved and increased by 1. This limits our options to the ages of 2 (prime when halved +1 is 2), 4 (half +1 is 3, prime), and 8 (half +1 is 5, prime).
  • John cannot be 2, since that's not reasonable for the context, so we're left with 4 and 8.
  • If Angie is 13 and John is 4, Michael would be 17, which is prime, so that doesn't fit the non-prime requirement for Michael. Therefore, John cannot be 4.
  • If Angie is 17 or 19 and John is 8, then Michael would be 25 or 27, neither of which are prime, satisfying all the conditions.
  • We can then conclude that John is 8 years old.
User Sergio Rodrigues
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