he earn nth. cuz he sold it to the guy 9 bucks earn 1 dollar but when he buy it back with 10$he lost 1$.and when he sell it out when 11$ just got his money back !!he earn NOTHING they a raiseing the price up
$2 bucks la, 公仔箱論壇8 ~; ?) F# K. c1 T" ^8 e& O0 u" q9 I
assume he has $9 at the beginning, minus $8 for the first purchase and sold it for $9, his balance should be $10, then he used $10 to purchase, the balance is $0, afterward, he got $11 back, his final balance would be $11, $11 - $9 = $2 in total