The number of chickens and sheeps on the Old MacDonals farm is 39 and 16 respectively.
let
x + y = 55
2x + 4y = 142
Multiply (1) by 2
2x + 2y = 110
2x + 4y = 142
4y - 2y = 142 - 110
2y = 32
y = 32/2
y = 16
substitute y = 16 into (1)
x + y = 55
x + 16 = 55
x = 55 - 16
x = 39
Learn more about equation:
https://brainly.com/question/1214333
#SPJ1