SOLUTION: For which of the following values of N is 3N � 1 not a prime number? (a) 1 (b) 2 (c) 3 (d) 4 (e) 6

Question 339036: For which of the following values of N is 3N � 1 not a prime number?
(a) 1 (b) 2 (c) 3 (d) 4 (e) 6
Answer by nyc_function(2741) (Show Source): You can put this solution on YOUR website!
A prime number can be divided, without a remainder, only by itself and by 1. For example, 17 can be divided only by 17 and by 1.
The only even prime number is 2. All other even numbers can be divided by 2.
We must replace N by every number on the list to find the one that does not yield a prime number.
Let N = 1, 2, 3, 4 and 6 individually in the given expression and simplify.
3N - 1
3(1) - 1 = 3 - 1 = 2...That's not it.
3N - 1
3(2) - 1 = 6 - 1 = 5...That's not it.
3N - 1
3(3) - 1 = 9 - 1 = 8...This is it! There is no need to go further with the process.
Understood?
The answer is CHOICE (C).

RELATED QUESTIONS
For which of the following values of N is 3N � 1 not a prime number? (a) 1 (b) 2 (c) 3 (answered by nyc_function)

How many different prime numbers are factors of 1988? (Note: The number 1 is not a... (answered by nerdybill)

How many different prime numbers are factors of 1988? (Note: The number 1 is not a... (answered by ankor@dixie-net.com)

If n is an integer, which of the following represents an odd number? (A) 2n+3 (B) 2n (answered by Alan3354)

If n is an integer, which of the following CANNOT be a factor of 3n + 4 ? (A)... (answered by MRperkins)

Which expression represents the sum of the following? (3n / n^2 - 2n + 1) + (5 / n... (answered by checkley77)

For which of the following values of m will the value of 3m - 1 be greater than 10 ? (answered by london maths tutor)

For which of the following values of k will the value of 3k-1 be greater than 10 ?... (answered by checkley77)

for which of the following values of m will the value of 3m � 1 be greater than 10... (answered by josmiceli)