To determine the number of deer in a game preserve, a conservationist catches 810 deer, tags them and lets them loose. Later 684 deer are caught; 171 of them are tagged. How many deer are in the preserve?

Answer 1

let the number of deer be x
prob that a deer is tagged = 810/x

so 810/x = 171/684
171x = 810(684)
x = 810(684)/171 = 3240