Manhatten DS problem

[shaden]

The question is this:

If x and y are positive integers and 3x + 5 < x + 11, is x a prime number?

Forget about statements 1 and 2. You can simplfy the above to x < 3. Therefore, since x is a positive int, it can only be 1 or 2, which are both prime #'s right? Therefore without any statements, you know it is a prime # correct?

[ninkorn]

you forgot to change the signs. X>3

Not X<3

[lachlanc]

no, he didn't.

3x + 5 < x + 11

subtract x and 5 from both sides => 2x < 6 => x < 3

by definition, 1 is not prime. So the object of the problem is to find if x = 1 or 2.

[shaden]

I assumed 1 was prime since it is divisble only by 1 and itself. Thanks