This question asks if the following equation is valid:
k _ (l + m) = (k _ l) + (k _ m)
where _ can be one of the following operations:
+, -, x (ie: addition, subtraction, or multiplication)
the statements are :
(1) k _ 1 != 1 _ k for some k
(2) _ represents subtraction
The answer is 'D' because it claims 'subraction' is the operation.
I don't understand why since
k - (l + m) does NOT equal (k - l) + (k - m)
Is this an error in the book or am I missing something?
Thanks
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Question about problem 89 from OG 11 (page 285)
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Brent@GMATPrepNow
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Keep in mind that the over-reaching question here is "Do we have enough information to determine whether we can answer the question "Is the equation k _ (l + m) = (k _ l) + (k _ m) valid?"gmattic wrote:This question asks if the following equation is valid:
k _ (l + m) = (k _ l) + (k _ m)
where _ can be one of the following operations:
+, -, x (ie: addition, subtraction, or multiplication)
the statements are :
(1) k _ 1 != 1 _ k for some k
(2) _ represents subtraction
The answer is 'D' because it claims 'subraction' is the operation.
I don't understand why since
k - (l + m) does NOT equal (k - l) + (k - m)
Is this an error in the book or am I missing something?
Thanks
(2) If the operation is subtraction then the equation is NOT valid.
So, using the information in statement (2), we have definitively answered the question "Is the equation k _ (l + m) = (k _ l) + (k _ m) valid?" The answer to this question is a resounding no.
So, statement (2) is sufficient
Brent Hanneson - Creator of GMATPrepNow.com
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glorydefined
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Hi,
This ones pretty simple, the question asks if the following eq is valid :
k _ (l + m) = (k _ l) + (k _ m)
for the above eq to be valid "_" should be multiplicaiton. so basically the question is asking whether "_" is multiplication or not.
stmt 1: k _ 1 != 1 _ k for some k
this statement says "_" is subtraction. (only then the above eq will be valid). So it answers our main question, which is "k _ (l + m) = (k _ l) + (k _ m)" is invalid. Hence SUFFCIENT
stamt 2: _ represents subtraction
this statement also says the same thing. Which makes the main question invalid. Hence SUFFCIENT.
ANSWER D
This ones pretty simple, the question asks if the following eq is valid :
k _ (l + m) = (k _ l) + (k _ m)
for the above eq to be valid "_" should be multiplicaiton. so basically the question is asking whether "_" is multiplication or not.
stmt 1: k _ 1 != 1 _ k for some k
this statement says "_" is subtraction. (only then the above eq will be valid). So it answers our main question, which is "k _ (l + m) = (k _ l) + (k _ m)" is invalid. Hence SUFFCIENT
stamt 2: _ represents subtraction
this statement also says the same thing. Which makes the main question invalid. Hence SUFFCIENT.
ANSWER D
GMAT/MBA Expert
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Brent@GMATPrepNow
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I didn't comment on statement (1) because I wasn't sure what != means.gmattic wrote:This question asks if the following equation is valid:
k _ (l + m) = (k _ l) + (k _ m)
where _ can be one of the following operations:
+, -, x (ie: addition, subtraction, or multiplication)
the statements are :
(1) k _ 1 != 1 _ k for some k
(2) _ represents subtraction
The answer is 'D' because it claims 'subraction' is the operation.
I don't understand why since
k - (l + m) does NOT equal (k - l) + (k - m)
Is this an error in the book or am I missing something?
Thanks
If this is just a typo and statement (1) is meant to read k _ 1 = 1 _ k for some k then _ could be any of the 4 operations when k=1.
What is the original wording of the question?
Brent Hanneson - Creator of GMATPrepNow.com
!= means 'does not equal'. Sorry for the confusion, its how you denote 'does not equal' in programming.Brent Hanneson wrote:I didn't comment on statement (1) because I wasn't sure what != means.gmattic wrote:This question asks if the following equation is valid:
k _ (l + m) = (k _ l) + (k _ m)
where _ can be one of the following operations:
+, -, x (ie: addition, subtraction, or multiplication)
the statements are :
(1) k _ 1 != 1 _ k for some k
(2) _ represents subtraction
The answer is 'D' because it claims 'subraction' is the operation.
I don't understand why since
k - (l + m) does NOT equal (k - l) + (k - m)
Is this an error in the book or am I missing something?
Thanks
If this is just a typo and statement (1) is meant to read k _ 1 = 1 _ k for some k then _ could be any of the 4 operations when k=1.
What is the original wording of the question?
Thanks for the answer folks.
