|
Author |
Message |
|
TAGS:
|
|
|
Director
Joined: 18 Apr 2005
Posts: 553
Location: Canuckland
Followers: 1
Kudos [?]:
3
[0], given: 0
|
If x,y, and z are positive integers such that 0 < x < [#permalink]
 27 May 2005, 16:02
Question Stats:
0% (00:00) correct
 0% (00:00) wrong based on 0 sessions
If x,y, and z are positive integers such that 0 < x < y < z and x is even, y is odd, and z is prime, which of the following is a possible value of x + y + z ?
A) 6
B) 11
C)19
D) 26
E) 29
|
|
|
|
|
|
|
Manager
Joined: 07 Mar 2005
Posts: 95
Followers: 1
Kudos [?]:
2
[0], given: 0
|
2+5+19 =26
D.
Just started plugging away. Probably took me 2:30 - 3:00 min. Is there an easier way to do this?
|
|
|
|
|
|
Director
Joined: 18 Apr 2005
Posts: 553
Location: Canuckland
Followers: 1
Kudos [?]:
3
[0], given: 0
|
tkirk32 wrote: 2+5+19 =26
D.
Just started plugging away. Probably took me 2:30 - 3:00 min. Is there an easier way to do this?
 of course, with the right approach, it would take 30 sec, maybe less, including reading the question.
|
|
|
|
|
|
SVP
Joined: 05 Apr 2005
Posts: 1745
Followers: 2
Kudos [?]:
17
[0], given: 0
|
Re: PS, 700+ level [#permalink]
27 May 2005, 18:56
sparky wrote: If x,y, and z are positive integers such that 0 < x < y < z and x is even, y is odd, and z is prime, which of the following is a possible value of x + y + z ?
A) 6
B) 11
C)19
D) 26
E) 29
to minimize the time, use POE first. so eliminate B, C and E because x + y + z cannot be odd integer.
then, plug in. using plugging in, you can easily eliminate A because 6 is smaller than the required integer. so D (26) is the only possible integer.
|
|
|
|
|
|
Manager
Joined: 07 Mar 2005
Posts: 95
Followers: 1
Kudos [?]:
2
[0], given: 0
|
see, I am just not good enough to see that 2 odds plus an even must be even.
I know the concept, just cant seem to apply it when I need to.
|
|
|
|
|
|
Director
Joined: 18 Feb 2005
Posts: 720
Followers: 1
Kudos [?]:
2
[0], given: 0
|
let the
even number x =2*k
odd number = 2*k+1
prime number is odd always uneless it is 2.
add them 4*k + 1 + odd number(prime number) = some even number
x has to be atleast 2 ......answer is 26
|
|
|
|
|
|
Senior Manager
Joined: 15 Mar 2005
Posts: 432
Location: Phoenix
Followers: 1
Kudos [?]:
7
[0], given: 0
|
Re: PS, 700+ level [#permalink]
28 May 2005, 03:35
sparky wrote: If x,y, and z are positive integers such that 0 < x < y < z and x is even, y is odd, and z is prime, which of the following is a possible value of x + y + z ?
A) 6
B) 11
C)19
D) 26
E) 29
Sorry guys, saw this thread late, but thought would chip in with my thoughts. My 2 cents on this one -
Min x = 2. Min y = 3. Min z = 2. Thus x + y + z >= 7. Thus A is ruled out.
You can start a process of elimination by considering the primes. Basic requirement is this:
Subtract a prime from the given option, and your answer should be odd.
If this hits, then the prime should be greatest of the three numbers.
Since odd number - prime would always be even (unless the prime is 2, which is smallest number, so inadmissible) - since all other primes are odd, no odd number can be the answer.
Thus 26.
Btw Sparky, POE is Process of Elimination (unless I am grossly mistaken )
_________________
Who says elephants can't dance?
|
|
|
|
|
|
Current Student
Joined: 28 Dec 2004
Posts: 3439
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 11
Kudos [?]:
134
[0], given: 2
|
D it is...
sorry late on the board...
someone told me on GMAT whenever you have which of following type question start with the answer choice E and start plugging in numbers....
I did that, took about 1 min to figure D it is...
|
|
|
|
|
|
Senior Manager
Joined: 21 Mar 2004
Posts: 447
Location: Cary,NC
Followers: 2
Kudos [?]:
2
[0], given: 0
|
took me 2-3 mins but it cleared quite a few concepts.
I think plugging in numbers might be quick if you get it quickly but it is possible that it might take time too.
x,y are odd and even.
x + y is odd.
z is prime and not =2. z is odd.
( All prime numbers are odd except 2. Here x,y are smaller than z so z cannot be 2)
Now we know that ODD + ODD = EVEN
The only even answers are 6 and 26.
6 can be easily verified as not sufficient.
Ans is 26.
HTH
_________________
ash
________________________
I'm crossing the bridge.........
|
|
|
|
|
|
Senior Manager
Joined: 15 Apr 2005
Posts: 425
Location: India, Chennai
Followers: 1
Kudos [?]:
1
[0], given: 0
|
I saw this question very late. However here is my approach and answer.
0 < x < y < z
X is even, Y is odd and Z is prime. 2 is the only even prime number, and z cannot be equal to 2, and so z should be an odd prime number.
even + odd + odd = even
From the answer choices there are only 2 choices 6 and 26 that are even. If x = 2 then the answer choice cannot be 6, hence 26 is the only option.
Thanks
Sreeni
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
close
