I am new to trading so my question might seem obvious or stupid to some but here goes.
Exchanges often quote crypto pairs in a specific order, i.e. ETH/BTC but not very often (if at all) BTC/ETH. Also XRP/BTC but not BTC/XRP.
What if someone wants to buy BTC by selling XRP or ETC. Is it possible? If yes, how is that value calculated?
e.g. looking at ETH/BTC on Binance today the value is $8,101.82. What if I want to buy BTC from ETH (i.e. BTC/ETH), how do we calculate that value given the prices an exchange gives on ETH/BTC?