It is so very simple and quick to get the answer, especially since, IF you need it, you can use the calculator that comes with your computer. But since you are obviously not able to do so, the answer is 157.1 (approx).
.7 of 1100 = .7 x 1100 = 770
0.0091
27.5
the starting concentration divided by 1100
7 percent out of 1100 is 77.
0.0182
0.0136
0.0045
2.75
52.381
100
It is: 1100