Domesticated cats can live to about 12 to 18 years of age. Even though, some can even live upto 20 years of age. This is entirely dependent on the healthcare provided, the diet and the environment in which your cat's lives.
You are asking for the human equivalent of a cat's lifespan right. A cat's 24 years of life is equal to a human's 100 years of life but most cats don't reach this age as the average lifespan is 14-18 years (which is around 70 years for a human).