25
200
5000
200
The series appears to be decreasing by progressively smaller factors. Each number is obtained by dividing the previous number by a decreasing factor: 5000 divided by 5 gives 1000, 1000 divided by 5 gives 200, and 200 divided by 5 gives 40. Continuing this pattern, 40 divided by 5 gives 8, so the next number in the series is 8.
25 x 200 = 5000
2% of 1 billion divided by 5000 = 20000000 divided by 5000 = 4000.
555.5556
0.028
5000
5000 / 7 = 714.28571
5000
200 is 4% of 5,000.