My question has to do with calculating cost basis on cryptocurrencies.

Real life example:

1) Bought 5.75 Ethereum (ETH) valued at $4086.60 @ $710.71 USD per coin.

2) Few days later transferred Ethereum to another exchange and bought 5,795.3610 XRP for 5.9344 ETH. Price 0.001024 ETH per XRP. (I did not exchange for USD.)

So what would my cost basis be? Would it be the original $4086.60 when I purchase Ethereum the few days before? Do I need to figure out the average price Ethereum was on the day I exchange ETH for XRP and use that as a selling price for ETH?