SOLUTION: the sum of five consecutive prime numbers is even. is it true or false? and what is its counterexample?

Algebra.Com
Question 1179725: the sum of five consecutive prime numbers is even. is it true or false? and what is its counterexample?

Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39621)   (Show Source): You can put this solution on YOUR website!
2, 3, 5, 7, 11 ------one even number and four odd numbers. Sum is even.

3, 5, 7, 11, 13 ------odd number of odd numbers. Sum is odd.


That should be clear enough.

Answer by ikleyn(52824)   (Show Source): You can put this solution on YOUR website!
.

It is not always true.


It is false sometime.

It is true in one and only one case: if the first of five consecutive prime numbers is 2.


Otherwise, it is FALSE: as a counter-example, consider the sequence of five consecutive primes 3, 5, 7, 11, 13 with the sum of 39.



RELATED QUESTIONS

Is it possible for the statement "If n and m are two even numbers, then n+m is also even" (answered by ikleyn)
Determine if this conjecture is true. If not, give a counterexample. The sum of two... (answered by richard1234)
when a odd number is added to the product of two even numbers, the answer is even. what... (answered by stanbon)
True or false: every whole number greater than 10 is the sum of two or three consecutive... (answered by josgarithmetic)
is the following conditional statement true or false? If false provide a counterexample. (answered by xinxin)
the difference of the aboslute value of two numbers is the same as the difference of the... (answered by Theo)
Decide whether each statement is true or false. If false, provide a counterexample. If (answered by solver91311)
The sum of a set of five consecutive even numbers is 140. What is the sum of the next set (answered by josgarithmetic)
found the counterexample to show that the following statement is false. The sum of two... (answered by Alan3354)