With help from other people in the forum I was able to fix my model and got the right answers for Q1-3. Now I am doing Q4 which asked me to modify the part. However I am not getting the correct answer. I assumed the same depth for both "pockets" since I couldn't identify the information from the question. I am guessing I might had done something wrong with either or both of these pockets tho... It will be greatly appreciated if any of you can take a look!