A plane flying at an altitude of 33,980 feet descends 5148 feet two times before ascending 1761 feet. What is the current altitude of the plane ?

Answer 1

Starting at 33980 feet, descending means losing altitude, ascending gaining.

33980 - 2(5148) + 1761 (lose 5148 two times, then gain 1761).

33980 - 10296 + 1761.

Take it from there.