The math answer is:. The cheetah 'gains' (100-80)=20 km on the gazelle, so it takes (70/20)=3.5 hours to close the gap and catch its prey. ///// The real-world answer is:. Neither animal can keep up that speed for more than a few minutes. Either the gazelle totally runs out of gas and gets caught in a short time, or else the cheetah poops out and goes off to find some nearer prey.
