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In a certain pond

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In a certain pond

by ektamatta » Thu May 29, 2008 7:44 pm
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

OA is C
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by swdatta » Thu May 29, 2008 8:14 pm
Number of total fish tagged in the pond 50 (from the first catch). In the second catch 2 out 50 fishes were tagged - 4%.
The question says that "the percent of tagged fish in the second catch approximates the percent of tagged fish in the pond" meaning that if the pond has x fishes .04x = 50. x =1250.
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by Brent@GMATPrepNow » Tue Jun 11, 2019 6:58 am
ektamatta wrote: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

OA is C
We can use equivalent ratios here.

We're told that the proportion of tagged fish in the 50-fish SAMPLE is equal to the the proportion of tagged fish in the ENTIRE pond.

So, (# tagged fish in SAMPLE)/50 = (total # tagged fish)/(total # of fish in POND)

Let x = # of fish in the entire pond.

We get: 2/50 = 50/x
Cross multiply to get 2x = (50)(50)
x = 1250
Answer: C

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by Scott@TargetTestPrep » Fri Jun 14, 2019 9:41 am
ektamatta wrote: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 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

Answer: C

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