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GMAT Club Olympics 2025 (Day 4): African grey parrots cannot detect

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AviNFC

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Reqd. is whether wavelength of W <620?

1. No info for W...NOT SUFFICIENT
2. if V=100, W=200..YES...but if V=500, W=1000...NO...NOT SUFFICIENT

Together,
W=2*300=600..YES....SUFFICIENT

Ans C

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Bunuel

African grey parrots cannot detect colors with wavelengths greater than or equal to 620 nanometers. Can an African grey parrot detect color W?

(1) Color V has a wavelength of 300 nanometers.
(2) The wavelength of color W is twice that of color V.

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asked: Can parrot detect color W

needed: wavelength of colour W

Statement 1: collar V wavelength given. Not sufficient So B,C,E

Statement 2: color W wavelength = 2 * color V wavelength. We do not know the color V wavelength . So C, E

Combined 1 and 2 : Color W wavelength can be calculated . So sufficient. Hence Option C answer.

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Fairly easy question

wavelength >=620, parrots can't detect the color. Is wavelength of W color is >=620 or <=620?

1. color V is 300nm. It does not help with the answer
2. color W= 2color V. We don't know anything about V wavelength that can help to determine the color of W.

Now let's see 1 and 2 together so, it saves V =300nm

Hence, W=2*300= 600nm which is less than 620 nm so it can detect the color W

Hence answer is C. 1 and 2 together answer the question

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African grey parrots cannot detect colors with wavelengths greater than or equal to 620 nanometers. Can an African grey parrot detect color W?
P>=620 nm can’t detect these colors
Can P detect W color?

(1) Color V has a wavelength of 300 nanometers.
V= 300 nm, no information about color W
Insufficient

(2) The wavelength of color W is twice that of color V.
W=2V, we don’t V’s wavelength
Insufficient

(1)&(2) W=2V=2*300=600 nm<620 nm
Yes, W color can be detected
Sufficient

C

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Given in the question, Wavelength that can be detected < 620nm.

Statement 1: Wavelength of V =300nm
Statement 2: Wavelength of W= 2 X (wavelength of V)
Statement 1 & 2: Wavelength of W=600nm
Combining this information with the given information in question,
we can say, African grey parrot can detect colour W.
So question can be answered when both statements are considered together
Therefore, Option C

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Can an African grey parrot detect color W?
Only when color W wavelengths < 620 nm.
Need information about color W wavelength.

(1) don’t know anything about color W’s wavelength => Insufficient

(2) don’t know anything about W as well as V’s value, so can’t find W. => Insufficient.

(1) + (2)
(1): V = 300 nm
(2): W = 2 × 300 = 600 nm
Since 600 < 620 nm => African parrot can detect color W
==> Sufficient

Answer: C

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Statement I alone is insufficient as it only tells about V and not W. Statement II alone is insufficient as it only states the relation bw V & W but not their values. But both I & II together provide V= 300 & W= 2V = 600 viz. <620 thus visible

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African grey parrots cannot detect colours with wavelengths greater than or equal to 620 nanometres.

Coming to the solution,

Point 1 gives the wavelength of V but not W. we need to know the wavelength of W for the solution

Point 2 gives the value of W is twice the wavelength of V= 300 * 2= 600 wavelengths which is less than 620.

Hence , African grey parrot detect colour since W has wavelength less than 620.

Answer is B , statement 2 is sufficient to answer the question, but statement 1 is not sufficient .

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Statement (1) gives us the wavelength of colour V which is not what the question is asking, therefore, statement (1) alone is not sufficient.
RULE OUT OPTION A
Statement (2) is meaninful only when we use value given in statement (1) , therefore, statement (2) alone is also not sufficient.
RULE OUT OPTION B
Combining information from both the statement gives us information that colour W wavelength is 600 which is less than 620 and therefore can be seen.
We get an answer by combining information given in both the staements, therefore, OPTION C.
RULE OUT OPTION B

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Ques: Is the color W above the wavelength or below the wavelength?

Stmt 1: No value for W - Insufficient

Stmt 2: V = 200, W = 400 - Yes and V = 330, W = 660 - No - Insufficient

By combining the statements we see W = 600 nm - Sufficient

Option C

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Color is detectable if wavelength <620 nm
Can African grey parrot detect colour W?

Statement 1:
Color V has a wavelength of 300 nanometers.
We have no info regarding color W
Hence insufficient

Statement 2:
The wavelength of color W is twice that of color V.
We dont know the value of either V or W
Hence insufficient

Combining 1 & 2
V = 300
W = 2V = 600nm

Since 600 <620 nm hence yes we have unique value

C is correct ans

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Statement 1 is not sufficient.
Statement 2 is also not sufficient.

Combining the 2 tells us color W has a wavelength of 600 which is detectable by African grey parrots.
Hence the correct answer is C.

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Lets the given statements,

Statement (1): Color V has a wavelength of 300 nanometers.

This statement provides information about color V, but tells us nothing about color W.
Therefore, Statement (1) alone is not sufficient.

Statement (2): The wavelength of color W is twice that of color V.
W =2×V

This statement provides a relationship between the wavelengths of V and W, but does not give us the specific wavelength of either.
Therefore, Statement (2) alone is not sufficient.

Combining Statement (1) and Statement (2):
From Statement (1), we have V=300 nm.
From Statement (2), we have W =2×V
W =2×300 nm
W =600 nm

Now we compare W with the detection threshold for African grey parrots.
The parrot cannot detect colors with wavelengths ≥620 nm.
Our calculated wavelength for color W is 600 nm.

Since 600<620, it means W is less than the threshold at which they cannot detect colors.
Therefore, an African grey parrot can detect color W.

Therefore, the statements together are sufficient.

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Given:- African grey parrots cannot detect colors with wavelength greater than or equal to 620 nanometers
To find:- Can an African grey parrot detect color W

(1) we have provided that wavelength for color V is 300 nanometers. Since we have no information about color W's wavelength so, it's not sufficient.

(2) Wavelength of color W is twice that of color V but we do not know the wavelength of color V so, it's not sufficient.

Combining (1) & (2), we get
we know wavelength of Color V which is 300 nanometers and also, wavelength of color W is twice of color so we can easily fin wavelength of color W which will be 600 (2*300) nanometers.
Since, cold W has wavelength 600 nanometers which is less than 620 nanometers, hence, African grey parrot can deter color W. Hence, it is sufficient.

Answer Choice (C)

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Target question is Wavelength of W<620nm

(1) Color V has a wavelength of 300 nanometers.
Info regarding V is irrelevant. Insufficient

(2) The wavelength of color W is twice that of color V.
Without knowing the value for wavelength V, we can not ascertain if W<620nm. Hence Insufficient

Option (1) & (2) together ---> V=300nm, so W=2V= 600nm, hence W<620nm. Sufficient

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AGP can detect wavelength <620 nm, can AGP detect color W? or Is color W wavelength < 620 ?

(1) V has wavelength = 300 nm , can't calculate if W (wavelength) < 620 AD , BCE can be answer
(2) wavelength (W) = 2* Wavelength (V) , don't know value of W or V wavelength B , CE can be answer

Combining V = 300 nm , then W = 600.
Wavelength W< 620 ( is W wavelength < 620 = NO, definitive answer) So C is correct.

TIP: Striking off answers like I did ( AD ) can help in guess if you have less time or you need to guess the answer.

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Correct answer should be E.

Statement I alone:
No information about color W is present. Insufficient.

Statement II alone:
W = 2V
But we do not know the wavelength of V. Insufficient

Statement I and II combined:
W = 2 * 300 = 600nm

Now we only know the upper limit of wavelength which grey parrot can detect. No information is present regarding the lower limit. It may be the case that grey parrots can only detect wavelengths in the range. 605nm >WL< 620nm, Therefore insufficient.

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It was a dicey question for me, but still going with E

The reason being that, we are just told that African Parrots cannot seen colours with wavelengths>=620 nm. We don't know anything about the colours below 620, maybe they can see some wavelengths, maybe they can't. Maybe they can see everything but the 600 nm wavelength, but that information is not given.

Hence went with E.

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i am going for C on this question.

the question is basically asking if W >= 620
i) V = 300 ( not sufficient as we dont know the relationship between W and V)
ii) W = 2 V ( not sufficient as we dont have the value of V )

both together ( sufficient as we know that V = 300 then W = 600 meaning W is not >= 620 )

C

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The question is simple, is W<620.
1. Says about color V, but we need about color W. Hence insufficient.
2. Says W=2V. but we don't know about V. Hence it could be 20 or 2000. So W could be 40 or 4000. Hence we cannot say. Insufficient.

But together. V=300, W = 2*300 = 600 which is less than 620. Hence yes.
So the answer is C.

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