Using Superposition Theorem, calculate current through resistor \( R_{2} \) in Fig. 1 below, given that \( E_{1}=15 \mathrm{~V} \), \( \mathrm{E}_{2}=10 \mathrm{~V}, \mathrm{R}_{1}=2 \mathrm{k} \Omega, \mathrm{R}_{2}=3 \mathrm{k} \Omega, \mathrm{R}_{3}=6 \mathrm{k} \Omega \). Indicate the direction of current through \( \mathrm{R}_{2} \).