Item 10 a cheetah that is running 90 feet per second is 120 feet behind an antelope that is running 60 feet per second. how long will it take the cheetah to catch up to the antelope?

Answer: 4 second

To answer this question you need to know the difference between the cheetah and the antelope speed.

It would be: 90 feet/s - 60feet/s = 30 feet/s

That means the distance between the cheetah and the antelope will shorten 30 feet every second. After that divide the distance with the speed difference:

120 feet / (30feet/s) = 4 second