Where's Olin?

     Mississippi Map Turtles have experienced a steady decline in numbers over the last few years. This is due to pollution, people, and invasive species .Here, I am going to give you a problem and work through it with you.

  A picture of Olin. My Mississippi Map Turtle.

To figure out the number of  Mississippi Map Turtles along a tributary of the great Mississippi River, herpetologist have begun to record and mark the map turtles they find. Last year herpetologist caught and marked 80 turtles. Then, they caught 30 more within a time frame of 6 months, and it is found that 10 of those are are marked. Estimate how many map turtles are in the river.

First lets set this problem into two ratios that are equal to each other.

         X  turtles      =              80 turtles        
  30 marked turtles             10 marked turtles

Now we simply cross-multiply.

X * 10 = 30 * 80

Now we divide both sides by 10.

X=        30(80)       
                 10

X= 240

The estimated number of Mississippi Map Turtle is 240.

Here's a  Link  if your interested in learning more about simple probability.