Question 621491
To determine the number of deer in a game preserve, a conservationist catches 823 deer, tags them and lets them loose.
 Later, 692 deer are caught; 173 of them are tagged.
 How many deer are in the preserve?
:
Let d = actual number of deer
:
Write ratio equation: 
{{{d/823}}} = {{{692/173}}}
Cross multiply
173d = 823 * 692
173d = 569516
d = 569516/173
d = 3,292 deer