sara inspected the horses and hens in her farm one morning. Afterwards, we could not remember how many animals of each kind she had, but knew the total number of these animals was 27, her own age in 1997. She also knew that the total number of legs was 70, the year in which she was born. How many horses does Sara Have? You may assume that each animal has the usual number of legs. Outline clearly the strategy you used to answer this question.

Answer 1

use a system of equations

let x = the number of horses
and y = the number of hens

hens have 2 legs, and horses have 4

x + 7 = 27
(the number of horses plus the number of hens equals 27 animals)

4x + 2y = 70
(four legs on every horse plus 2 legs on every hen equals 70 legs)