$($ Difficulty: ${?}^{****})$

Given the following circuit with resistors $R_1=1\mathrm{.}0,R_2=2\mathrm{.}0,R_3=3\mathrm{.}0,R_4=4\mathrm{.}0,R_5=5\mathrm{.}0,$

and $R_6=6\mathrm{.}0,$ with ${}_1=10\mathrm{.}0V,{}_3=10\mathrm{.}0V,$ and ${}_5=15\mathrm{.}0V.$

$($a$)$ What is the current $I_2$ passing through resistor $R_2??$

$($b$)$ What is the current $I_5$ passing through resistor $R_5??($ give both magnitude and direction $)$