# Integers

• Jan 8th 2013, 02:24 PM
tahirakw
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
• Jan 8th 2013, 02:49 PM
abender
Re: Integers
Have you made an attempt? Do you know what prime and composite numbers are?
• Jan 8th 2013, 02:57 PM
tahirakw
Re: Integers
My answer is 9. A prime 3,5,7,11. 3,5,7,11,13,17,19,23,27.
• Jan 8th 2013, 03:00 PM
tahirakw
Re: Integers
typo 27 in not a prime
• Jan 8th 2013, 03:00 PM
abender
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!
• Jan 8th 2013, 03:03 PM
tahirakw
Re: Integers
Yes 29. and 2 you are right.
• Jan 8th 2013, 03:07 PM
HallsofIvy
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.
• Jan 8th 2013, 03:10 PM
abender
Re: Integers
Don't kids play Number Munchers any more?
• Jan 9th 2013, 07:09 AM
tahirakw
Re: Integers
I guess not. Thanks