Solve this :
(0.85% of 405) + (2.25% of 550) = ?

$$\left( {0.85\% {\text{ of }}405} \right) + \left( {2.25\% {\text{ of }}550} \right)$$
$$ = \left( {\frac{{85}}{{100}} \times \frac{1}{{100}} \times 405} \right) + $$     $$\left( {\frac{{225}}{{100}} \times \frac{1}{{100}} \times 550} \right)$$
$$\eqalign{ & = \frac{{225}}{{10000}}\left( {153 + 550} \right) \cr & = \left( {\frac{{225 \times 703}}{{10000}}} \right) \cr & = 15.8175 \cr} $$