microeconomics-----------fixed costs variable and marginal. check please?

Can you pleasre check my answers?? I hate this class, i get no help from the instructor until after answers are submitted (its an online class):

Total

Output Cost

0 $ 50

1 120

2 170

3 200

4 275

5 360

6 450

1. The firm’s total fixed cost of producing the 2nd unit of output is:

170

2. The firm’s total variable cost of producing 4 units of output is: 1100

3. The firm’s average total cost of producing 5 units of output is: 72

4. The firm’s average fixed cost of producing 6 units of output is: 75

5. The firm’s marginal cost of producing the 3rd unit of output is: 0.015