Eur/usd , usd/chf

What causes eur/usd and usd/chf to be reversed?
already tryed to google for answer but my poor english didnt allow it to happen.

It’s correlation, - ‘In statistics, dependence refers to any statistical relationship between two random variables or two sets of data.’

The CHF is closely related to the EUR, but it’s inverse becasue it’s X/USD rather than USD/X