Search found 39 matches
- by woo
Fri Sep 25, 2009 2:35 am- Forum: Data Sufficiency
- Topic: 20 k is divisible
- Replies: 7
- Views: 5744
In the first line, why do you have to multiply by 2?grockit_jake wrote: For (2):
[n/10]*[10-n)/ 9]*2 = 7/15
n(10-n) = 42
10n - n^2 = 21
n^2 - 10n + 21 = 0
(n-3)(n-7)=0
n=3,n=7.
A it is.
Is it because we have to consider 2 cases: one with defective chosen first and the other with normal bulb chosen first?
- by woo
Fri Sep 25, 2009 2:28 am- Forum: Data Sufficiency
- Topic: light bulbs-probability
- Replies: 8
- Views: 2700
It seems we all agree that modifying the question gets us x^y=(5^2)(1/3)z Condition 1 says y is a prime. x must be an integer according to the question thus, z has to be multiple of 3. z can be 3, 6, 9, 12 and so on If you plug in 3 in z you get x^y=(5^2). Here x=5 However, if you plug in 12 you get...
- by woo
Sat Sep 19, 2009 5:40 am- Forum: Data Sufficiency
- Topic: MGmat number properties
- Replies: 7
- Views: 1975
we know from condition 2 that
200p^2+200p-14400=0
p^2+p-72=0
(p-8)(p+9)=0
Therefore, p=8,-9
but p cannot be negative
thus, p=8 hence sufficient
- by woo
Sat Sep 19, 2009 5:13 am- Forum: Data Sufficiency
- Topic: Cutting Edge Knives
- Replies: 3
- Views: 1530
About B, I am not so sure why it must be that 15% is dress shirt. It could be something else. Though, I don't know how you can categorize shirts.
- by woo
Mon Sep 14, 2009 5:48 am- Forum: Data Sufficiency
- Topic: Phil's Shirts
- Replies: 4
- Views: 1702
IMO D but I have different reasoning for condition 2.
a-2b is same as a+b-3b.
therefore, according to condition B
a+b-3b=3c where c is an integer.
a+b=3c+3b
a+b=3(c+b)
Therefore, a+b is a mulitple of 3.
- by woo
Mon Sep 14, 2009 4:22 am- Forum: Data Sufficiency
- Topic: MGMAT: multiples
- Replies: 5
- Views: 2813
- by woo
Mon Sep 14, 2009 3:11 am- Forum: Data Sufficiency
- Topic: probability
- Replies: 3
- Views: 1360
I agree that the answer is A
But I have a different opinion about the second condition. There is a pair of integers that satisfies the condition 2: 4, 6.
But x and y don't have to be integers.
It could be that x=1 and y=sqr root 51.
Therefore B is not sufficient.
IMO A
- by woo
Wed Sep 09, 2009 4:58 am- Forum: Data Sufficiency
- Topic: What is the perimeter of a parallelogram ?
- Replies: 2
- Views: 1127
What I meant is that according to spidey's note GMAT uses 'distinguish between X and Y' form for x and y that are completely different things and 'distinguish x from y' form for x and y that are very similar like genuine painting and fake one but, looking at sentences in the original post GMAT is no...
- by woo
Sat Sep 05, 2009 5:34 am- Forum: Sentence Correction
- Topic: distinguish from or between... No certain answer!
- Replies: 2
- Views: 1305
distinguish from or between... No certain answer!
distinguish good paintings from poor ones distinguish the explosion of a large meteorite from the explosion of a nuclear weapon distinguish addictive from non-addictive drugs distinguish between a language and the sub-languages distinguish between messages triggered by pollen and messages triggered ...
- by woo
Tue Sep 01, 2009 6:59 am- Forum: Sentence Correction
- Topic: distinguish from or between... No certain answer!
- Replies: 2
- Views: 1305
The or without the?
Although it was expected that workers under forty would show hostility to the plan, the research report indicates that both younger and the older people approve of governmental appropriations for Social Security. (A) younger and the older people (B) younger people and the older (C) the younger and t...
- by woo
Tue Sep 01, 2009 5:59 am- Forum: Sentence Correction
- Topic: The or without the?
- Replies: 0
- Views: 1705
I think there is something wrong in this question because I can actually figure out the answer without any conditions.. Tell me what is wrong in my reasoning. The question is x^2 > y^2 ? By rearranging x^2 - y^2 > 0? We know that x^2 - y^2 is equal to (x-y)(x+y) thsu, (x-y)(x+y) > 0? From the questi...
- by woo
Sun Aug 30, 2009 7:48 pm- Forum: Data Sufficiency
- Topic: DS / x = 3y
- Replies: 6
- Views: 4540
Re: DS - 1
Hi there, Could you explain in the simplest this concept and how to resolve it Is xy > 1 ? (1) xyz = 1 (2) xz > 1 We all know that the answer is either C or E. First we combine condition 1 and 2. we know that xz is greater than 1 therefore, in order for condition 1 to hold y must be equal to 1/xz. ...
- by woo
Sun Aug 30, 2009 7:33 pm- Forum: Data Sufficiency
- Topic: DS - 1
- Replies: 4
- Views: 1460
We agree that it's not A, B or D. Condition 1 says both p and q are positive or negative. Condition 2 says when q is negative r is positive and vice versa. Combining the two we know that when q is negative and r is positive p is negative thus, pqr = positive coz p and r should have different signs w...
- by woo
Sun Aug 30, 2009 7:07 pm- Forum: Data Sufficiency
- Topic: Is pqr >0 ?
- Replies: 3
- Views: 1557
Dangling sentence?
With surface temperatures estimated at minus 230 degrees Fahrenheit, Jupiter's moon Europa has long been considered far too cold to support life, and with 60 square miles of water thought to be frozen from top to bottom. A. Europa has long been considered far too cold to support life, and with B. Eu...
- by woo
Sat Aug 22, 2009 7:06 am- Forum: Sentence Correction
- Topic: Dangling sentence?
- Replies: 1
- Views: 1372