Answer
Goldfish=43
Horse=64
Human=122
Work Step by Step
We know that the combined longest lifespan of a goldfish , Horse and Human is 229
Goldfish=x
Horse=x+21
Human =x+79
Goldfish+Horse+Human=229 we substitute with the above values
$ x+x+21+x+79=229$
$ 3x+100=229$ subtract 100 from both sides
$ 3x=129$ divide both sides by 3
$ x=43$
Goldfish=43
Horse=43+21=64
Human=43+79=122
