Results 1 to 9 of 9

Math Help - Integers

  1. #1
    Newbie
    Joined
    Jan 2013
    From
    Abington
    Posts
    15

    Integers

    Set S consists of integers from 2-30, inclusive. The number of composite numbers in S is how much greater than the number of prime numbers in S?

    A. 6 B. 7 C. 8 D. 9
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member
    Joined
    Mar 2008
    From
    Pennsylvania, USA
    Posts
    269
    Thanks
    37

    Re: Integers

    Have you made an attempt? Do you know what prime and composite numbers are?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Jan 2013
    From
    Abington
    Posts
    15

    Re: Integers

    My answer is 9. A prime 3,5,7,11. 3,5,7,11,13,17,19,23,27.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Jan 2013
    From
    Abington
    Posts
    15

    Re: Integers

    typo 27 in not a prime
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Senior Member
    Joined
    Mar 2008
    From
    Pennsylvania, USA
    Posts
    269
    Thanks
    37

    Re: Integers

    9\times 3 = 27, or, 3\times 3\times 3 = 27
    Did you mean 29 instead of 27?
    Also, don't forget that 2 is a prime!
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Newbie
    Joined
    Jan 2013
    From
    Abington
    Posts
    15

    Re: Integers

    Yes 29. and 2 you are right.
    Follow Math Help Forum on Facebook and Google+

  7. #7
    MHF Contributor

    Joined
    Apr 2005
    Posts
    14,971
    Thanks
    1121

    Re: Integers

    Yes, there are 9 more composites than primes. The primes are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29 so there are 10 primes out of the 29 numbers between 2 and 30, inclusive,leaving 29- 10= 19 composite numbers. 19- 10= 9.
    Follow Math Help Forum on Facebook and Google+

  8. #8
    Senior Member
    Joined
    Mar 2008
    From
    Pennsylvania, USA
    Posts
    269
    Thanks
    37

    Re: Integers

    Don't kids play Number Munchers any more?
    Follow Math Help Forum on Facebook and Google+

  9. #9
    Newbie
    Joined
    Jan 2013
    From
    Abington
    Posts
    15

    Re: Integers

    I guess not. Thanks
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: December 5th 2011, 11:47 PM
  2. Replies: 7
    Last Post: August 3rd 2010, 01:31 PM
  3. Matrix of integers whose inverse is full of integers
    Posted in the Advanced Algebra Forum
    Replies: 2
    Last Post: March 19th 2010, 02:02 PM
  4. Replies: 4
    Last Post: February 24th 2008, 03:08 PM
  5. Replies: 2
    Last Post: October 14th 2007, 03:18 PM

Search Tags


/mathhelpforum @mathhelpforum