If the integer x is divisible by 3 but not by 2, then which one of the ... ...
If the integer x is divisible by 3 but not by 2, then which one of the following expressions is NEVER an integer?
(A)
(B) ...
(C) ...
(D) ...
(E) ...
*This question is included in
Nova Math - Problem Set A: Substitution
Replies to This Thread: 1
|
----
Posted: 07/24/2012 18:53
For choice b, when you sub x=3 3/7 is not an integer... How do you know to sub another number? How come you don't try all numbers for all choices?
Reply 1 of 1
Replies to This Thread: 0
|
----
Posted: 07/13/2015 07:24
Reply: because the question says "NEVER"an integer. So you look for other possibilities. For questions with "never", "cannot be" process of elimination works quite good.
Good luck with your exam!
Contributor
Replies to This Thread: 0
|
----
Posted: 07/25/2012 01:58
For this kind of questions, we kind of have to pick numbers that prove the question wrong (in this case: to prove that it can be an integer, so we can eliminate it).
Contributor
Replies to This Thread: 0
|
----
Posted: 07/25/2012 02:00
Continued. For example: in choice A, the denominator is 2, so pick an x that is a multiple of 3, and an x that will make the numerator even, so that choice A would be an integer.
Contributor
Replies to This Thread: 0
|
----
Posted: 07/25/2012 02:03
Continued. For B, pick an x that is a multiple of 3, and also that is a multiple of 7 (since the denominator is 7), in order to make the value whole. That means x = 21. And so on. In conclusion, we have to think what numbers to pick, they are not random, but ones that would help us eliminate choices.
Replies to This Thread: 0
|
----
Posted: 08/22/2012 12:33
Choice B would also be an alternate answer. If X had a value of 9 (which is divisible by 3 but not by 2) then x/7 would also not be an integer. The problem says that it can NEVER be an integer. Isn't answer B also a possible solution?
Admin
Replies to This Thread: 0
|
----
Posted: 08/22/2012 12:44
Andrew, no. If it is an integer even once, then it is not an answer
Replies to This Thread: 1
|
----
If the integer x is divisible by 3 but not by 2, then which one of the ... ...
Posted: 08/24/2013 00:07
If x is 48, for example, it is evenly divisible by 24.
Admin
Reply 1 of 1
Replies to This Thread: 0
|
----
Posted: 08/24/2013 02:45
Hi A H,
If x = 48, then it is divisible by 2: 48/2 = 24.
But this is not allowed by the conditions of the problem: x is divisible by 3 but NOT by 2.
Nova Pres
