B757-200 Basic Weight ~60,000kg
307 Passengers @75kg = 23,050kg
Hand luggage (and there will be a LOT of it if it's a Hajj trip @5kg = 1,535kg
Total 84,585kg
235 pax (charter confgi) is a tight squeeze. No way could 307 passengers be on that aircraft, if a 757-300 then possibly (280 in charter config).
B757-200 MZFM = 83,500kg.
75kg (165 lb)may be considerd slim by UK standards. But that would be considered high by cartered Haji standards. 60kg (132lb) may be closer to the mark
B757-200 Basic Weight ~60,000kg
307 Passengers @60kg = 18,420kg
Hand luggage @5kg = 1,535kg
Total 79,955kg
Also, the Hajj flights are all adult!