Sally made the conjecture that the sum of any two prime numbers is a prime number.

Which equation is a counterexample to her conjecture?

A. 15+4=19
B. 2+5=7
C. 3+11=14
D. 2+11=13

Question

Sally made the conjecture that the sum of any two prime numbers is a prime number.

Which equation is a counterexample to her conjecture?


A. 15+4=19
B. 2+5=7
C. 3+11=14
D. 2+11=13

anonymous · Answer

@Deadpool117 @mathmate @mathstudent55

anonymous · Answer

._.

anonymous · Answer

what do u think?

anonymous · Answer

Maybe D or A

vocaloid · Answer

well, we want an example of two prime numbers added together to make a number that isn't prime, so between 19, 7, 14, and 13, which one is NOT prime?

anonymous · Answer

14 is not a prime number @Vocaloid

vocaloid · Answer

good job! so which one do you think is the answer?

anonymous · Answer

I think that the answer should be B

vocaloid · Answer

no, please try again and look at the answer choices...

which one has a sum of 14?

anonymous · Answer

Oh so the answer would be c

vocaloid · Answer

good

anonymous · Answer

@Vocaloid Thanks for the help