I saw that the lottery winning amount keeps changing every week. Is it progressive like the daily jackpot or is a btc price dependent prize pot?
It keeps on changing every week because every week as well winners will be announced. I think lottery has always to depend on BTC price on its prizepot and it's always $7500 (can't remember clearly if it has changed).
No, the amount of prize pool isn't fixed. It depends on total number of tickets.
Every week, 1/4 of value of total tickets is awarded to winners.
Below are value of prizes awarded to winners.
First winner: 1/8 of value of total tickets.
Second winner: 1/16 of value of total tickets.
Third winner: 1/32 of value of total tickets.
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