Question

Cows and Chickens

A chicken farmer also has cows for
a total of 30 animals, and the
animals have 66 legs in all.
How many chickens does the farmer have?

Answer 1

27 Chickens

Explanation:

Represent the chicken with A and the cows with B

Given

`A + B = 30`

A has 2 legs and B has 4; So:

`2A + 4B = 66`

Required

Determine A and B

Make B the subject of formula in the first equation

`B = 30 - A`

Substitute 30 - A for B in the second equation

`2A + 4(30 - A) = 66`

Open the bracket

`2A + 120 - 4A = 66`

Collect Like Terms

`2A - 4A = 66 - 120`

`-2A= -54`

Divide through by -2

`A = 27`

Hence, the farmer has 27 chickens