Although the fuel flow has remained the same according to the question, the aircraft has a higher groundspeed:

• Fuel flow = (Planned fuel remaining at ToC - Planned fuel remaining at TORDU) / Planned flight time from ToC to TORDU = [(360 kg - 241 kg) / 53] x 60 = 135 kg/hr.

The question asks the expected fuel remaining for the fuel check overhead TORDU at 19:42 (50 minutes after the TOC).

• In 50 minutes to TORDU, with a fuel flow of 135 kg/h, the aircraft would have burnt 112.5 kg of fuel.

Looking at the Top-Of-Climb Planned Fuel Remaining column, the pilot initially planned to have 360 kg, but he/she actually had 375 kg, as it is recorded in the ToC Fuel Check column.

• TORDU = 375 kg - 112.5 kg = 262.5 kg (263 kg)