In denominator 0.2 three times multiplied means (0.2)^3 and 0.04 also three times multiplied means (0.04)^3 so from both fractions we taking 2^3 common
[0.2)^3+(0.04)^3]
2^3[(0.1)^3+(0.02)^3
Then numerator and denominator having same value so they canceled each other 2^3 means 8
1/8 =0.125