answer
1). Airplane is flying at 14551 feet.
2). Height of the mountain is 4299 feet.
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1). An airplane starts at the level = 0 feet
It rose to the altitude = 21000 feet
It descends by the height due to clouds = 4329 feet
So the height of the airplane = 21000 - 4329
= 16671 feet
After giving pass to a plane it ascends by the height = 6333 feet
Now the height of the airplane = 16671 + 6333
= 23004 feet
Then the airplane descends again to give the pass to a airplane again.
Altitude after descending by 8453 feet = 23004 - 8453 = 14551 feet
Airplane is flying at 14551 feet.
2). Distance between the top of the mountain to the floor of the valley = 4392 feet
Valley is 93 feet below the sea level.
Therefore, the height of the mountain will be = 4392 - 93
= 4299 feet
hope this helps you