1. Culture A.
Since the number of cells increases by 200 each day and every day thereafter, then after seven days the number of cells will increase by

2. Culture B.
The initial number of cells was 1,000. Since the number of cells increases 8% each day and every day thereafter, then after seven days the number of cells will be

The number of cells that have grown by the end of the seventh day is
1,713-1,000=713.
Answer: option A -- Culture A: 1400 cells Culture B: 713 cells