Question 395370
On a farm there are chicken and horses.  There are a total of 79 heads and 176 legs.  How many chickens are on the farm?
<pre><font face = "batangche" color = "indigo" size = 4><b>

A horse has 1 pair of front legs and 1 pair of back legs.  A chicken
has only 1 pair of "front" legs, and no back legs.

Since there are 176 legs, there are 88 leg-pairs.  Each of the 79
heads has 1 front leg-pair under it, so 79 of the leg-pairs are front
leg-pairs, and the remaining 9 leg pairs are back leg-pairs.  They 
belong to the horses, so there are 9 horses, and the other 70 
animals are chickens.

Edwin</pre>