Question 887582
Think of the ratios of each animal to the body parts.


COWS:  4 legs per cow.  1 head per cow.

CHICKENS:  2 legs per chicken.  1 head per chicken.


The available heads and legs suggests you should account for heads and account for legs.  Notice that the ratio of any animal to heads is 1 to 1, so for 60 heads, Mr. Tucker must have 60 animals, combined chickens and cows.


p = how many chickens  (as in "poultry").
b = how many cows  (think, "bovine").

You know {{{highlight(p+b=60)}}}.


Now account for legs:
{{{p*2+b*4=200}}}
{{{2p+4b=200}}}
{{{highlight(p+2b=100)}}}


Two equations in two unknowns.  Finish the solution.