She was at 40 feet below, she swam up getting so she was then at 40-10 = 30 feet below sea level.
She the swan 4 feet down so she ended up at 30 + 4 = 34 feet below sea level.
The answer is 34 feet below sea level (-34)
Answer:
Kate.
Step-by-step explanation:

First we must apply the Quotient rule that states,

This means that our derivative becomes,

Now we need to calculate
and 


From here the new equation looks like,

And that is the final result.
Hope this helps.
r3t40