Answer: Her current depth is 106 feet below the sea level.
Step-by-step explanation:
Since we have given that
Distance a diver covered below sea level = 90 feet
Since it is below the sea level, so it will be written as (-) 90 feet.
After this, she descends at a steady rate of 6 feet per minute for 6 minutes.
So, Speed = 6 feet per minute
Time taken by him = 6 minutes
So, Distance covered = 
Again she descends by 36 feet which is written as (-) 36 feet.
So, she reached at

Again, she ascends 20 feet.
Since she ascends by 20 feet then it will be written as (+)20 feet.
So, she reached at

Hence, her current depth is 106 feet below the sea level.