Linguist: Plosives and fricatives are two classes of consonants.

Question

Linguist: Plosives and fricatives are two classes of consonants. A "voicing contrast" is a distinction between two consonants that are identical except that one is voiced and the other is unvoiced. In language family X, languages with voicing contrasts in their fricatives always have voicing contrasts in their plosives. This means that in that family, any given language has a voicing contrast in its fricatives __________ it has a voicing contrast in its plosives. In other words, a given language in that family lacks any voicing contrasts in its plosives __________ it lacks any such contrasts in its fricatives.

Select for First blank the word or phrase that most logically completes the statement with the first blank. And select for Second blank the word or phrase that most logically completes the statement with the second blank. Make only two selections, one in each column.

Select for  First blank  the word or phrase that most logically completes the statement with the first blank. And select for  Second blank  the word or phrase that most logically completes the statement with the second blank. Make only two selections, one in each column.

ID: 700253

KarishmaB · Accepted Answer

The question is based on your understanding of conditional statements.

You might want to review these two videos on my YouTube channel before looking at the solution:

Given: If F, then P
This is equivalent to: Only if P, then F
and also to: Only if not F, then not P

This means that in that family, any given language has a voicing contrast in its fricatives __________ it has a voicing contrast in its plosives.

If/Only if P, then F?
As I said above, it is equivalent to Only if P, then F. Hence "only if" (ANSWER)
Can "and" or "or" work here? No, not necessary. A given language may have no voicing contrasts in either or it may have voicing contrast in P, but not in F. What says that every langauge must have voicing contrasts in both or even one?
What about "until"? No. Until X, then Y means X is necessary for not Y. Not our structure.

In other words, a given language in that family lacks any voicing contrasts in its plosives __________ it lacks any such contrasts in its fricatives.

If/Only if no F, then no P?
As I said above, it is equivalent to Only if not F, then not P. Hence "only if" (ANSWER)
Similarly, "and", "or" or "until" do not work here too.

chetan2u · Answer

It is all about rearranging the statement -  languages with voicing contrasts in their fricatives always have voicing contrasts in their plosives.

This means voicing contrast in fricatives means voicing contrasts in their plosives. It would happen when  voicing contrasts in their fricatives(A)  is a part of  voicing contrasts in their plosives.(B)  .

In terms of If then sentence: it means If A then B.

(1) The other way to write this is A only if B, and this is exactly what blank 1 does. 
  any given language has a voicing contrast in its fricatives(A) __________ it has a voicing contrast in its plosive(B) 
(2) Another way to write If A then B is 'If not B, then not A'. This further becomes not B only if not A.
This is exactly the way blank 2 is written
 In other words, a given language in that family lacks any voicing contrasts in its plosives(not B) __________ it lacks any such contrasts in its fricatives(not A).

Hoehenheim , Hope it helps

Hoehenheim · Answer

Hi  chetan2u  ! I'm having trouble seeing 'only if' as the answer to the first blank. Can you please explain it?
I find 'and' more suitable.
The logic I followed is: The phrase states if vc in fricatives --> always vc in plosives.
The first blank states: "any given language has a voicing contrast in its fricatives __________ it has a voicing contrast in its plosives"
'and' stands to be more suitable as compared to 'only if', because the latter gives the implication that if A is true then so is B, And if B is true then so is A.
Which is not the case stated in the premise.
Please explain.

turd_fergsn · Answer

I watched your video thanks! But what I don't understand is why there can't be a scenario where there is a VC in P but not in F? Is it not saying that it is a necessary condition for there to be a VC in F it must have it in P? But it does not say that for there to be a VC in P there must also be in F

KarishmaB · Answer

Yes, there can be a scenario where there is a VC in P but not in F. Check out the highlighted in my response above. Can you point out where I implied that this is not possible?

nisen20 · Answer

first things first, here's the usage of only if from oxford dictionary:
https://www.oxfordlearnersdictionaries. ... #if_idmg_7
only if
(rather formal) used to state the only situation in which something can happen

Only if a teacher has given permission is a student allowed to leave the room.
Only if the red light comes on is there any danger to employees.

in the two examples above, only if is always followed by a neccesary condition, rather than a sufficient condition.

as far as i'm concerned, this question has nothing to do with "if, then" which indicates a sufficient condition.
i don't want to make it unnecessarily complicated by introducing those two concepts. so i'd like to call it a "one covers another" problem.

Quote:

In language family X, languages with voicing contrasts in their fricatives always have voicing contrasts in their plosives.

the prompt depicts an image that set P fully covers and goes beyond an area defined by set F.
for short, set F is a part of set P.

so it's clear the first blank should be filled with only if, because the existence of set F depends on the existence of set P.

Quote:

any given language has a voicing contrast in its Fricatives only if it has a voicing contrast in its Plosives.

but the second blank, if filled with only if, would be unreasonable.

Quote:

a given language in that family lacks any voicing contrasts in its Plosives only if it lacks any such contrasts in its Fricatives.

as i've reasoned above: set F is fully engulfed by set P, so lacking P determines lacking F; the reverse cannot be true.

i'd like to see official explanation, though we know it's not written by test makers themselves and always flawed.

mbaprepavi · Answer

For a more detailed explaination

Understanding the Original Statement 
The original statement is:
 
This means that within language family X, whenever a language has voicing contrasts in fricatives, it  must  also have voicing contrasts in plosives. In other words, having voicing contrasts in plosives is a  necessary condition  for having them in fricatives

How "Always" Becomes "Only If" 
The word  "always"  in the original statement establishes a consistent relationship:  every  time a language has voicing contrasts in fricatives, it also has them in plosives.
 
  Logical Translation :  If  a language has voicing contrasts in fricatives,  then  it has voicing contrasts in plosives.  
When we rephrase this relationship using  "only if" , we're emphasizing the  necessary condition :
 
 A language has voicing contrasts in fricatives  only if  it has voicing contrasts in plosives.  
This means that without voicing contrasts in plosives, it is  impossible  for the language to have voicing contrasts in fricatives
 
Difference Between "If" and "Only If" 
 "If"  and  "only if"  are used to express different types of logical conditions:
 
  "If"  introduces a  sufficient condition .
 
  Structure :  If  A, then B. 
  Meaning : Whenever A occurs, B occurs. A guarantees B, but B might occur without A.  
 
  "Only if"  introduces a  necessary condition .
 
  Structure : A occurs  only if  B occurs. 
  Meaning : A cannot occur without B. B is required for A, but B might occur without A.  
  
----------------------------------------------------------------------------------------------------------------

Examples to Illustrate the Difference 
 Example 1: Weather 
 
  If  it is raining, then the ground is wet.
 
 Rain is a  sufficient condition  for the ground being wet. 
 The ground can be wet for other reasons (e.g., sprinklers).  
 
 The ground is wet  only if  it is raining.
 
 Rain is a  necessary condition  for the ground being wet. 
 The ground cannot be wet unless it is raining.  
  
 Example 2: Academic Requirements 
 
  If  you score 90% or above, you will pass the exam.
 
 Scoring 90% is sufficient to pass, but you might pass with a lower score.  
 
 You will pass the exam  only if  you score 90% or above. 
 Scoring 90% is necessary to pass; you cannot pass without it.

Therefore, Coming back to the question:
 "Always"  in the original statement indicates that voicing contrasts in fricatives cannot occur without voicing contrasts in plosives.
 "Only if"  is used to express this necessary condition in logical terms.

micahman · Answer

https://gmatclub.com/forum/download/file.php?id=83156 Karishma you are contradicting yourself here? Not a does not imply not B so why are you saying it does here? GMAT-Club-Forum-xc69udlh.png

Adarsh_24 · Answer

OE:
Letting P denote “has a voicing contrast in its fricatives” and Q denote “has a voicing contrast in its plosives”, then the first identified sentence states that given P we have Q, or “if P then Q”, which is logically equivalent to “P only if Q”.

The correct answer is only if.

RO2
Letting P and Q be as above, we are to put the second identified sentence into the form “not-Q ______ not-P”. Since the contrapositive of the first identified sentence is “if not-Q then not-P”, which is logically equivalent to the first identified sentence, it follows that a logically equivalent restatement of the first identified sentence is “not-Q only if not-P”.

The correct answer is only if.

KarishmaB · Answer

Please go through the videos given in the links. " If A, then B" is equivalent to " Only if not A, then not B" We have converted the sufficient to necessary condition by switching to negatives. We are not talking about implications here. GMAT-Club-Forum-33ljq8ku.png

Aditi_03 · Answer

How does ' not-Q then not-P ' lead to ' not-Q only if not-P '? P is dependent on Q but it doesn't seem to be the other way round.

Also, can someone please explain this question (esp the 2nd blank) via a venn diagram?

PeachSnapple1 · Answer

Ah yes, the trio IF-ONLY IF-UNLESS on the GMAT. If you nail the concept, you can handle it very quickly. Otherwise, you will stare at the screen for 15 minutes. Took me 45 seconds.

From the prompt     --> we can infer:  if F (fricatives, whatever that means), then P (plosives) 
If F, then P = If (not P), then (not F) = Only if P, then F =  F only if P  (the first blank) =  Only if (not F), then (not P) (the contrapositive version, which is also the second blank)

When I have the time, I would definitely write the whole condition statement for my own sake on the GMAT Forum, but below is the short version:
If it's Husky, then it is a dog = If it's not a dog, then it's definitely not a Husky = Only if it's a dog can it be a Husky = It's a Husky only if it's a dog = Only if it's not a Husky, then it's not dog (tricky) = Unless it's a dog, it's not a Husky
I'd argue those 6 conditional statements cover 99% of the conditional question type.

kanikaa9 · Answer

After reading the question, clearly write down the conditional relationship mentioned

It says  "If VC in F, then VC in P"  - this is the first blank, we need a word that can be used in place of then, words that introduces necessary conditions like only if, only, unless.. from the available options "only if" makes sense 
 Contra-positive is "If not VC in P, then no VC in F"  (no can be changed for lack) - this is the second blank statement, we again need a word to replace then to introduce necessary condition and again "only if" makes sense.

And is never used to introduce necessary or even sufficient conditions.

Kudos please if you liked my explanation

PeachSnapple1 · Answer

The key phrase is   my friend. You will need to understand it very clearly.

For instance, if I say  . That means  . But does that mean  ? Hell no, because getting 805, in this example, is just a necessary condition. I will need other conditions, i.e. having decent WE, having good LORs.

So to sum up: Only if P, then Q = If (not P), then (not Q) = If Q, then P
Took it further a notch while applying the same logic: Only if (not P), then (not Q) = If not (not P), then not (not Q) = If P, then Q = If (not Q), then (not P)

Hope that make sense.

consistentprep · Answer

If X , then Y --> X , only if Y
If ~Y then ~X ---> ~Y , only if ~X

kayarat600 · Answer

I used if for thr sec9nd blank I don't think I'm wrong here

cheshire · Answer

It's  only if  because F always has P so for a language to be lacking P it must inherently be lacking F as well.

billyy · Answer

Hope this helps. I did not get this question right on the first try, but I was able to come up with this solution that can hopefully help you avoid the mental gymnastics. P = Having a voicing contrast in Plosives F = Having a voicing contrast in Fricatives Based on the second sentence, we know if F exists, then P has to exist. So we can say PF is a valid combination. That renders _F invalid (F exists w/o P). The other 2 possible combos are: _ _ (lacks both) and P_ (has P but lacks F). The passage suggests nothing about these 2, so going to go ahead and assume they are valid. PF YES _F NO _ _ YES P_ YES First blank: If you want to have F, you gotta have P. (1st combo) ==> Only If Second blank: Lacking P means lacking F (3rd combo since 2nd combo does not work) ==> Only If Let me know if y'all seeing any issues

Linguist: Plosives and fricatives are two classes of consonants.

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Linguist: Plosives and fricatives are two classes of consonants.

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