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# In a certain pond, 50 fish were caught, tagged, and returned

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Joined: 02 Sep 2009
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In a certain pond, 50 fish were caught, tagged, and returned  [#permalink]

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10 Jan 2014, 07:10
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Difficulty:

25% (medium)

Question Stats:

79% (01:48) correct 21% (02:11) wrong based on 579 sessions

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The Official Guide For GMAT® Quantitative Review, 2ND Edition

In a certain pond, 50 fish were caught, tagged, and returned to the pond. A few days later, 50 fish were caught again, of which 2 were found to have been tagged. If the percent of tagged fish in the second catch approximates the percent of tagged fish in the pond, what is the approximate number of fish in the pond?

(A) 400
(B) 625
(C) 1,250
(D) 2,500
(E) 10,000

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Re: In a certain pond, 50 fish were caught, tagged, and returned  [#permalink]

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10 Jan 2014, 07:10
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SOLUTION

In a certain pond, 50 fish were caught, tagged, and returned to the pond. A few days later, 50 fish were caught again, of which 2 were found to have been tagged. If the percent of tagged fish in the second catch approximates the percent of tagged fish in the pond, what is the approximate number of fish in the pond?

(A) 400
(B) 625
(C) 1,250
(D) 2,500
(E) 10,000

The percent of tagged fish in the second catch is 2/50*100 = 4%.

We are told that 4% approximates the percent of tagged fish in the pond. Since there are 50 tagged fish, then we have 0.04x = 50 --> x = 1,250.

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Re: In a certain pond, 50 fish were caught, tagged, and returned  [#permalink]

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10 Jan 2014, 11:09
Bunuel wrote:
The Official Guide For GMAT® Quantitative Review, 2ND Edition

In a certain pond, 50 fish were caught, tagged, and returned to the pond. A few days later, 50 fish were caught again, of which 2 were found to have been tagged. If the percent of tagged fish in the second catch approximates the percent of tagged fish in the pond, what is the approximate number of fish in the pond?

(A) 400
(B) 625
(C) 1,250
(D) 2,500
(E) 10,000

# of fishes caught in the 2nd catch = 50 and # of fishes which are tagged = 2 so %age = 4%
And after the 1st catch, the # of fish which are tagged are = 50 which is 4% of # of fishes in the pond, so total number of fishes = 25*50 = 1250 - Option C)
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Re: In a certain pond, 50 fish were caught, tagged, and returned  [#permalink]

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23 Apr 2014, 03:44
50 fish were tagged in first catch and returned to pond .

Second Catch ---- again 50 fish ---- only 2 were tagged were caught.

percent of tagged fish in the second catch approximates the percent of tagged fish in the pond

2/50 = x/100;
x=4%;
4% ------------------ 50 ;
100% ---------------??????

no of fish in pond = 1250;
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In a certain pond, 50 fish were caught, tagged, and returned  [#permalink]

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29 Jul 2016, 11:02
Hey Bunuel i have a query in this question
Here why arent we taking the number of tagged fishes as 48 as 2 fishes that were caught arent returned to the pond.
we have no evidence that the two fishes were returned to the pond
so (4/100)*number of fishes = 48
although no option is provided i think its answer should be 1200

Where am i wrong ?

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Re: In a certain pond, 50 fish were caught, tagged, and returned  [#permalink]

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29 Jul 2016, 11:23
1
stonecold wrote:
Hey Bunuel i have a query in this question
Here why arent we taking the number of tagged fishes as 48 as 2 fishes that were caught arent returned to the pond.
we have no evidence that the two fishes were returned to the pond
so (4/100)*number of fishes = 48
although no option is provided i think its answer should be 1200

Where am i wrong ?

cc-EMPOWERgmatRichC

True. If one of the options would have been 1200, then this could be a concern.

But I believe GMAC people are intelligent enough to avoid such options that cause confusions.

So, since we donot have any option that matches per your assumption, we need to consider 50 tagged fishes only.

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Re: In a certain pond, 50 fish were caught, tagged, and returned  [#permalink]

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29 Jul 2016, 11:28
abhimahna wrote:
stonecold wrote:
Hey Bunuel i have a query in this question
Here why arent we taking the number of tagged fishes as 48 as 2 fishes that were caught arent returned to the pond.
we have no evidence that the two fishes were returned to the pond
so (4/100)*number of fishes = 48
although no option is provided i think its answer should be 1200

Where am i wrong ?

cc-EMPOWERgmatRichC

True. If one of the options would have been 1200, then this could be a concern.

But I believe GMAC people are intelligent enough to avoid such options that cause confusions.

So, since we donot have any option that matches per your assumption, we need to consider 50 tagged fishes only.

Nopes bruh..!
I disagree . I think we are really missing something here .
Abhishek009 has stopped doing quant i guess else he would have been the first one to respond on this
Lets wait for Bunuel to respond
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In a certain pond, 50 fish were caught, tagged, and returned  [#permalink]

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29 Jul 2016, 12:08
Hi stonecold,

There are a few different ways to address the interpretational 'issue' that you're talking about:

To start, regardless of how you interpret the prompt, the question ultimately asks for the APPROXIMATE number of fish in the pond - your way of interpreting the question leads to the SAME correct answer. Thus, it doesn't really matter that you didn't get to 1250 exactly.

Second, IF the question expected you to calculate a result by 'ignoring' the 50 fish that were caught the second time, then it would have asked for the number of REMAINING fish in the pond (which the prompt did not do). By extension, you would have to question your interpretation of the wording (and possibly consider an alternative interpretation - which you seem to refuse to do). While minor interpretational 'biases' can sometimes happen in GMAT questions, the answer choices will be written so that there can only be one correct answer. If "your answer" isn't there, then you have to consider how you interpreted the given information and adjust your work accordingly.

Third, from a ratio standpoint, the 50 fish 'subgroup' that was caught the second time IS, mathematically speaking, part of the total number of fish in the pond (so you can't ignore that group when calculating the total number of fish in the pond).

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Re: In a certain pond, 50 fish were caught, tagged, and returned  [#permalink]

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14 Sep 2018, 09:32
Bunuel wrote:
The Official Guide For GMAT® Quantitative Review, 2ND Edition

In a certain pond, 50 fish were caught, tagged, and returned to the pond. A few days later, 50 fish were caught again, of which 2 were found to have been tagged. If the percent of tagged fish in the second catch approximates the percent of tagged fish in the pond, what is the approximate number of fish in the pond?

(A) 400
(B) 625
(C) 1,250
(D) 2,500
(E) 10,000

We are given that 50 fish were caught, tagged, and returned to the pond, and that a few days later, 50 fish were caught again, of which 2 were tagged. Thus, the percentage of tagged fish is 2/50 = 1/25 = 4%.

Since the the percentage of tagged fish in the second catch approximates the percentage of tagged fish in the pond, the approximate number of fish in the pond is:

0.04(total fish) = 50

total fish = 50/0.04 = 5000/4 = 1250

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Re: In a certain pond, 50 fish were caught, tagged, and returned &nbs [#permalink] 14 Sep 2018, 09:32
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