Can you help ? Please

Question

An airplane started at 0 feet. It rose 21,000 feet at takeoff. It then descended 4,329 feet because of clouds. An oncoming plane was approaching, so it rose 6,333 feet. After the oncoming plane passed, it descended 8,453 feet. At what altitude was the plane flying?

Answer 1

Khairah this is similar to your stock market question. It is an addition subtraction problem. Rising is addition, descending is subtraction. You can tell because it started out at 0 altitude (it just so happens I am also an airline captain so this is quite a coincidence! lol). When the plane descends, simply subtract, and when it rises, add. Let me know if you have any more trouble.