( 0.013 )^3 + 0.000000343 ( 0.013 )^2 - 0.000091 + 0.000049 = \,?

Answer: Option B

Given expression :
$$\begin{array}{rl}& \frac{{\left(0.013\right)}^3+0.000000343}{{\left(0.013\right)}^2-0.000091+0.000049}\\ & a=0.013\text{ and }b=0.007\\ & =\left(\frac{a^3+b^3}{a^2-ab+b^2}\right)\\ & =a+b\\ & =0.013+0.007\\ & =0.020\end{array}$$