SSC CGL 21-August-2017 Reasoning question 3

Select the related number from the given alternatives.
0.5 : 2 :: 0.125 : ?
Options:
1) 6
2) 16
3) 8
4) 12
Correct Answer: 8
Solution:
0.5 : 2 :: 0.5 * 0.5 * 0.5 : 2 * 2 * 2(8)