Answer:
-10,000 / -2000, although 10,000/2000 gives the same answer.
Step-by-step explanation:
The equations -10,000/2000 and 10,000/-2000 are negative, and negative days do not make sense, thus eliminating those answers.
Also, she wants to descend 10,000 feet, so that makes it -10,000 int he equation.
That's a 33% increase.
I calculated this using the formula:

Where n = the new value (16 in your question), o = the old value (12 in your question) and the result is outputted as a percent increase. You can check that this is correct by finding 33% of 12, adding the result to 12, and checking that the result equals your "new" number.
Note that 33% is only an approximation as your question requires a number rounded to the nearest whole.
Hmm idk hard one jnmmdmkrkror
You could distribute this expression to get and even MORE simplified expression. Add the two terms in the parentheses together so that you get 4(7x). Now you can simply multiply 4 by 7x which would equal 28x. The new expression is 28x.