Help?!?!Which of the following is true?
A 21 is a composite number because one and twenty-one are its only factors.
B 13 is a prime number because it is only divisible by one and itself.
C 16 is a prime number because it is divisible by 4.
D 28 is a composite number because 82 is a prime number.
(Thanks

Question

Help?!?!Which of the following is true?
  A  21 is a composite number because one and twenty-one are its only factors.
  B  13 is a prime number because it is only divisible by one and itself.
  C  16 is a prime number because it is divisible by 4.
 D   28 is a composite number because 82 is a prime number.
(Thanks<3)

zzr0ck3r · Answer

b... 21/3 = 7, 16/8 = 2 28/14 = 2

anonymous · Answer

Prime numbers can only be divided by itself and 1.
Composite numbers are every other number that can be divided in ways other than 1 and itself.  13 is a prime number.

zzr0ck3r · Answer

1 is not prime also