1 nguoi mua 2 cai quat dien , moi cai gia 1000000 dong . Nguoi do ban cai quat thu nhat bi lo 12% so voi tien mua cai quat do .Tuy vay sau khi ban 2 cai quat nguoi do van lai 40000 dong > Hoi nguoi do da ban cai quat thu 2 lai bao nhieu % so voi tien mua quat?