Question

To determine the number of beavers in a conservation​ area, a researcher catches and marks 119 beavers. Then the researcher releases them. Later 89 beavers are caught and it is found that 39 of them are tagged. About how many beavers are in the conservation​ area?
​(Round to the nearest whole number as​ needed.)

PLEASE HELP, DUE ON MARCH 21, 2019. THANK YOU!

Answer 1

Let x be the total number of beavers. We mark 119 out of x beavers. Then, we found 39 marked beaver out of 89 caught beavers. So, if we build the proportion

$119 \div x = 39 \div 89$

we get, solving for x,

$x = \dfrac{119\cdot 89}{39} \approx 272$

So, it is reasonable to suppose that there are about 272 beavers in total. Note that this is an estimate, both numerically and conceptually, since we have no information about the set of beavers caught at the beginning and the end of our experiment.