Confusion with formula

how runners per age formula is total runners/(oldest-youngest) in one of my project?can anyone explain me what this formula signifies,i am confused with this formula…!

Hello and welcome to the forum!

I think that we are going to need some more context to know what this formula signifies. Do you have more information you can share?

actually i am analyzing data of csv file from boston marathon 2017 results in excel using some online course video.So they were using the above formula.But i was not able to comprehend