Question

Jessie lives in a farm and only has 2 animals, chickens and rabbits. One day he decided to count the total number of heads and legs of his animals. He told his friends that there were 30 heads and 76 legs in all.
How many chickens does Jessie have on his farm?
How many rabbits does Jessie have on his farm?

Answer 1

Let x represent number of rabbits and y represent number of chickens.

We have been given that Jessie told her friends that there were total 30 heads for both animals. This means that there are total 30 animals.

$x+y=30...(1)$

$y=30-x...(1)$

We have been given that Jessie only had chicken and rabbits. We know that a rabbit has 4 legs, so total number of legs for x rabbits would be $4x$.

We know that a chicken has 2 legs, so total legs of y chickens would be $2y$.

Since all animals has 76 legs in all, so we can represent this information in an equation as:

$4x+2y=76...(2)$

Upon substituting equation (1) in equation(2), we will get:

$4x+60-2x=76$

$2x+60=76$

$2x+60-60=76-60$

$2x=16$

$\frac{2x}{2}=\frac{16}{2}$

$x=8$

Therefore, Jessie have 8 rabbits on his farm.

Number of chickens would be $y=30-x\Rightarrow 30-8=22$.

Therefore, Jessie have 22 chickens on his farm.