math riddle

posted by .

Estimate a population:

To study a species of fox, a team captures and tags 25 foxes from a large forest and then releases them. The following week they capture 15 foxes and find 5 are tagged. Estimate the number of foxes in the forest.


This is a proportion problem.
We know that 25 are tagged.
Let P denote the population, then
25:P=5:15
That is, the ratio of the tagged to the population should be approximately the ratio of the caught tagged to the caught untagged. Thus
(25*15)/5= P
The main hypotheses used is that the tagged have had sufficient time to be randomly dispersed throughout the population and that the sample is collected randomly from the population.


what roger said he seems to be a smart person!


Ahhh!! I see! It is a small population of foxes (being that after a full week, 5 of the original 25 were caught (in a small group of 15).

So, in the beginning, the 25 foxes (sample) of the whole forest, and the next sample, was 5 of the 15. The # of foxes chosen from whole pop. (that's where you got ratio 1 from.

75!!!


Yes! That's the idea here. We're using a sample to make some estimate of the population. However, in my post I see I stated it incorrectly. I should've stated that the ratio is caught tagged to total caught, not just total caught untagged.
The answer you should get is 75 as an estimate for the population. I should comment that there is a probability distribution called the hypergeometric distribution based on this sampling technique, but that will have to wait for a more advanced course.
Well done!


i think its 40 that's a tricky!


Now quit guessing and reason it out.


If A=1+r^a+r^2a+r^3a+.......................to infinity

B=1+r^b+r^2b+................to infinity

then find a/b=?????

78\9

a=7,b=5

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. PreCalculus

    How do i find the phase shift in this problem Naturalists find that the populations fo some kinds of predatory animals vary periodically. Assume that the population of foxes in a certain forest varies sinusoidally with time. Records …
  2. Pre Calc

    Naturalists findthat the populations of some kinds of predatory animals vary periodically. Assume that the population of foxes in a certain forext vareis sinusoidally iwth time. REcord started being kept when time t = 0 years. A minimum …
  3. PreCalc

    Naturalists find that the populations of some kinds of predatory animals vary periodically. Assume that the population of foxes in a certain forest varies sinusoidally with time. Records started being kept when t = 0 years. A minimum …
  4. Algebra

    Foxes and rabbits. The ratio of foxes to rabbits in the Deerfield Forest Preserve is 2 to 9. If there are 35 fewer foxes than rabbits, then how many of each are there?
  5. Math

    A population of 75 foxes in a wildlife preserve quadruples in size every 15 yr. The function y= 75 * 4^x , where x is the number of 15 yr periods, models the population growth. How many foxes will there be after 45 years?
  6. Statistics

    Can someone help me do this problem? A group of environmentalist are trying to estimate the population of the state rid in clear view park. They capture a sample of 500 birds in early spring and tag them. in august they capture 215
  7. Math

    3. A fish and game warden captures and tags 66 deer in a local forest. A month later he captures 100 deer and that 17 of them are tagged. Estimate the actual number of deer in the forest. A) 149 B)1,022 C) 578 D) 389*** 4. Lucy wants …
  8. Urgent math

    please help The fox population in a certain region has a relative growth rate of 7% per year. It is estimated that the population in 2005 was 19,000. (a) Find a function n(t) = n0ert that models the population t years after 2005. n(t) …
  9. Algebra

    I know I can use the population growth formula. here is the question; The fox population in a certain region has a relative growth rate of 7% per year. It is estimated that the population in 2005 was 19,000. (a) Find a function n(t) …
  10. math

    Santiago, a park ranger, was trying to estimate the number of catfish in a lake. He randomly caught 32 catfish, tagged them, and let them go. Six months later, he surveyed fisherman at the lake about how many catfish they caught that …

More Similar Questions