Answer: For daily, 13.3 (rounded) per day to pay back the 1200$, and 1.46% (rounded) daily as well.
Step-by-step explanation:
For interest (daily), it would be 1.46666667$ (also rounded) daily for the money required. So about Now, it does depend on what you're going for, so you can add up the daily for the 1.2k for however long your looking for, same with the interest. The 11% would be 132 in all.
Now if we want how much he has to pay left, we just see how much he needs to pay at first (assuming it's like this)-> 1200 + 132(11% interest) which is 1332.
Now we subtract what he as already payed (200+150) which is 350. So 1332-350=982
So the answer just depends on what your looking for :D
Hope this helped :3