To determine the number of trout in a lake, a conservationist catches 180 trout, tags them and throws them back into the lake. later, 48 trout are caught; 12 of them are tagged. how many trout would the conservationist expect to be in the lake?

The ratio of the trout with tags that are caught and the total trout with tags is first calculated.

     r = 12 trout / 180 trout = 1/15

Then, we divide the number of trouts caught without tag by the value obtained above.

     N = (48 - 12) / (1/15) = 540

Then, we add the number obtained above and 180.
     T = 540 + 180 = 720

ANSWER: 720