中一数学题.只有英文.
Jackyused$40000tobuy5000dollsfromatoymanufacturer.HedoubledthepriceforeachdollandsoldthemintheLunarNewYearMarket.Afterthemarketwasclosed,750dollswereleftunsold.
问:WhatwasJacky'sprofitpercentifalltheunsolddollsweredonatedtocharities?