<PRE><B>Question 1132356</B>
Old McDonald is told that he has a total of 20 chickens and cows
a + b = 20
 his hired hand also tells him that there are 64 legs of chickens and cows.
2a + 4b = 64
Simplify,divide by 2
a + 2b = 32
 How many of each are there
subtract the 1st equation from the above equation
a + 2b = 32
a + b = 20
---------------subtraction eliminates a, find b
0 + b = 12 cows
then
20 - 12 = 8 chickens
;
:
See if that checks out
2(8) + 4(12) = 
16 + 48 = 64
</PRE>