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Scientists tag 100 salmons in a river. Later, they caught 50 salmons. Of these, 2 have tags. Estimate how many salmons are in the river.

 

tysm for any help

 Dec 29, 2020
 #1
avatar+117546 
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Just a simple proportion

 

2 / 100  =   50   /  N          cross-multiply

 

2N  = 100 * 50

 

2N =  5000

 

N  =5000/2   =  2500 salmon

 

Another way to see this is to  note that 1/50  of the salmon are tagged

 

So....there are 50 times as  many as we  find  tagged

 

So...if we  find  50 tagged....then  50 * 50    = 2500  

 

cool cool cool

 Dec 29, 2020
 #2
avatar+476 
+2

Tysm CPhill!

 Dec 29, 2020

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