Math
posted by Dylan .
Can you please help me figure out how i go about figuring the following problem? .... A farmer has both pigs and chickens. There are 78 feet and 27 heads. How many pigs and how many chickens are there? ..... I am not sure what to do to figure it out. thanks in advance for your help ...

Let x=number of pigs
Let y=number of chickens
There are two equations with these two unknowns. Assume that the animals have the normal number of heads and feet for their species.
Number of heads:
x + y = 27
Number of feet:
4 * x + 2 * y = 78
Sove this equation set for x and y.
Hint:
Multiply the top equation by 2 and subtract it from the bottom to get rid of y. Sove for x. Substitute the x value into the first equation to find the y value.