Em tham khảo nha:

\(\begin{array}{l}
NPK:16 - 16 - 13\\
 \Rightarrow \% N = 16\% ;\% {P_2}{O_5} = 16\% ;\% {K_2}O = 13\% \\
\text{ Giả sử có 100g phân bón trên }\\
{m_{{P_2}{O_5}}} = 100 \times 16\%  = 16g \Rightarrow {n_{{P_2}{O_5}}} = \dfrac{{16}}{{142}} = \dfrac{8}{{71}}\,mol\\
{n_P} = 2{n_{{P_2}{O_5}}} = \dfrac{{16}}{{71}}\,mol\\
 \Rightarrow \% {m_P} = \dfrac{{31 \times \dfrac{{16}}{{71}}}}{{100}} \times 100\%  = 6,99\% \\
{m_{{K_2}O}} = 100 \times 13\%  = 13g \Rightarrow {n_{{K_2}O}} = \dfrac{{13}}{{94}}\,mol\\
{n_K} = 2{n_{{K_2}O}} = \dfrac{{13}}{{47}}\,mol\\
 \Rightarrow \% {m_K} = \dfrac{{39 \times \dfrac{{13}}{{47}}}}{{100}} \times 100\%  = 10,79\% 
\end{array}\)