Answer:
He has 30 penguins and 10 cats.
Step-by-step explanation:
Let's define the variables:
C = number of cats.
P = number of penguins.
We know that he has a total of 40 pets, then:
C + P = 40
We also know that the total heads (40 heads, each animal has one) plus the number of wings (P*2, each penguin has 2) is equal to the number of feet of his pets (4*C + 2*P, because each cat has 4 paws, and each penguin has 2)
Then we have the equation:
40 + 2*P = 4*C + 2*P
Notice that in the second equation we have the term 2*P in both sides of the equation, then we can just subtract 2*P in both sides to get:
(40 + 2*P) - 2*P = 4*C + 2*P - 2*P
40 = 4*C
Now with this, we can find the value of C.
40/4 = C = 10
Then he has 10 cats.
Now we can replace this in the equation:
P + C = 40
to find the value of P
P + 10 = 40
P = 40 - 10 = 30
P = 30
He has 30 penguins.
