A $60\mathrm{.}0-$ resistor is connected in parallel with a $155\mathrm{.}9-$ resistor. This parallel group is connected in series with a $17\mathrm{.}8-$ resistor. The total combination is connected across a $18\mathrm{.}0-$V battery. Find $($a$)$ the current and $($b$)$ the power dissipated in the $155\mathrm{.}9-$ resistor.