\(n_{Ag_2O}=\dfrac{4.64}{232}=0.02\left(mol\right)\)
\(m_{dd_{HNO_3}}=300\cdot1.59=477\left(g\right)\)
\(Ag_2O+2HNO_3\rightarrow2AgNO_3+H_2O\)
\(0.02............................0.04\)
\(m_{AgNO_3}=0.04\cdot170=6.8\left(g\right)\)
\(m_{dd}=4.64+477=481.64\left(g\right)\)
\(C\%_{AgNO_3}=\dfrac{6.8}{481.64}\cdot100\%=1.4\%\)