Arithmetic on today's supply, not a forecast. It assumes nothing about whether Stellar could attract that much money.
A coin's market capitalisation is its price multiplied by the number of coins in circulation. Stellar has 35,134,151,599 XLM in circulation at $0.1779 each, which is $6.25B. Holding that supply still and putting XRP's $85.4B in its place gives $2.4308 per XLM.
Stellar would have to take on $79.15B of new money to get there. A 13.7x move is large: it happens, and it usually needs the whole market to grow instead of one coin to take share from another.
Supply is held still, and in practice it moves: coins are minted, burned and unlocked, and every one of those changes the price a given market capitalisation implies. The figure also says nothing about whether the money exists to buy XLM at that level, which is the part that actually decides a price.
$2.4308 per XLM. That is XRP's current market capitalisation of $85.4B divided across the 35,134,151,599 XLM in circulation.
13.7x. Stellar trades at $0.1779 today and XRP's market cap is $85.4B against Stellar's $6.25B.
No. It is one division: XRP's market capitalisation spread over the supply of XLM that exists today. It assumes nothing about whether Stellar could attract that much money, and it holds the supply still when in practice supply changes.
It sets it. Market cap is price times circulating supply, so the same $85.4B of market cap spread over more coins gives a lower price per coin. This uses the 35,134,151,599 XLM in circulation now.