A certain heat engine does $10\mathrm{.}0$ kJ of work and $8\mathrm{.}00$ kJ heat transfer occurs to the environment in a cyclical process.

$($a$)$

What was the heat transfer $($in kJ$)$ into this engine?

kJ

$($b$)$

What was the engine's efficiency $($in percent$)?$

$\%$