Question

1
A farm raises pigs and chickens. The farmer has a total of
10)
66 animals. One day he counts the legs of all his animals
and realizes he has a total of 174 legs. How many pigs
does the farmer have?

Answer 1

Let p = number of pigs and c = number of chickens.
p + c = 66 and 4p + 2c = 174.

From the first, c = 66 − p. Substitute:
4p + 2(66 − p) = 174 → 4p + 132 − 2p = 174 → 2p = 42 → p = 21.

So the farmer has 21 pigs (and 45 chickens).