Cynthia made the conjecture that the sum of any prime number and any composite number is a composite number.

Which equation is a counterexample to her conjecture?

A.

5 + 8 = 13

B.

11 + 2 = 13

C.

11 + 9 = 20

D.

13 + 2 = 15

Question

Cynthia made the conjecture that the sum of any prime number and any composite number is a composite number.

 

Which equation is a counterexample to her conjecture?
	
	
 
A.
	

5 + 8 = 13
	
 
B.
	

11 + 2 = 13
	
 
C.
	

11 + 9 = 20
	
 
D.
	

13 + 2 = 15

anonymous · Answer

@SuperflyTyGuy  @maddiemsp plz help

perl · Answer

here is an example of a counterexample
3 is prime , 8 is composite.  is the sum composite?

perl · Answer

3 + 8 = 11, but 11 is prime (not composite) . 
so 3,8 is a counterexample. 
now can you answer the question