GRE Prep Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
QOTD#14 If w is a non-positive integer, which of the
[#permalink]
16 Nov 2016, 13:16
16 Nov 2016, 13:16
1
1
Expert Reply
10
Bookmarks
00:00
Question Stats:
11% (00:47) correct
88% (00:44) wrong based on 367 sessions
Hide Show timer Statistics
If w is a non-positive integer, which of the following must be positive?
Indicate all possible value
A. \(−3w\)
B. \(2w + 10\)
C. \(w^4\)
D. \(w^0\)
E. \(−w + 0.5\)
Indicate all possible value
A. \(−3w\)
B. \(2w + 10\)
C. \(w^4\)
D. \(w^0\)
E. \(−w + 0.5\)
Drill 4
Question: 7
Page: 294
Question: 7
Page: 294
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: QOTD#14 If w is a non-positive integer, which of the
[#permalink]
02 Jan 2017, 17:08
02 Jan 2017, 17:08
6
1
Bookmarks
sandy wrote:
If w is a non-positive integer, which of the following must be positive?
Indicate all possible values.
A. −3w
B. 2w + 10
C. w^4
D. w^0
E. −w + 0.5
Indicate all possible values.
A. −3w
B. 2w + 10
C. w^4
D. w^0
E. −w + 0.5
Drill 4
Question: 7
Page: 294
Question: 7
Page: 294
Show: :: OA
D and E
There's a slight problem with answer choice D.
If we let w = 0 (a non-positive integer), then w^0 = 0^0 and 0^0 is not defined (see page 141 of the Official Guide to the GRE - 3rd edition)
If 0^0 is not defined, we cannot say that 0^0 is positive.
So, there's only answer correct answer: E
Cheers,
Brent
General Discussion
Re: QOTD#14 If w is a non-positive integer, which of the
[#permalink]
16 Nov 2016, 13:23
16 Nov 2016, 13:23
1
Expert Reply
Explanation
Remember to Plug In multiple times for must be questions. First, use an easy number, such as −1, and try it in each choice. All of the answers are positive, so don’t eliminate anything. Can we eliminate anything by making w smaller? A number such as −10 will allow us to eliminate choice (B), but everything else is still positive. But can w = 0? Non-positive just means the number can’t be positive—it doesn’t mean it can’t be zero.
Hence options D and E are correct.
Note: Option B is negative if w is large enough.
Remember to Plug In multiple times for must be questions. First, use an easy number, such as −1, and try it in each choice. All of the answers are positive, so don’t eliminate anything. Can we eliminate anything by making w smaller? A number such as −10 will allow us to eliminate choice (B), but everything else is still positive. But can w = 0? Non-positive just means the number can’t be positive—it doesn’t mean it can’t be zero.
| w = -1 | w = 0 | |
| 3w | 3 | 0 |
| 2w+10 | 8 | 10 |
| w^4 | 1 | 0 |
| w^0 | 1 | 1 |
| -w+0.5 | 1.5 | 0.5 |
Hence options D and E are correct.
Note: Option B is negative if w is large enough.
