WORKERS TOTAL PRODUCT AVERAGE PRODUCT MARGINAL PRODUCT
1 6 6  
2 16 8 10
3 28 9.3 12
4 42 10.25 14
5 56 11.12 14
6 66 11 10
7 69 9.8 3
8 70 8.7 1
9 69 7.6 -1
Answer
Assuming one factor is fixed, the addition of extra workers will result in increasing returns followed eventually by diminishing returns.