Answer
$|W| = 0.0714 \space J $
Work Step by Step
To find the work done, use the following equation
$|W| = \frac{|Q_L|}{K_C}$
Where
$K_C = \frac{T_L}{T_H - T_L} $
and $W = 1.0 J$
Substitute all the unknowns into the equation
$|W| = (1.00 J)( \frac{T_H - T_L}{T_L})$
$|W| = (1.00 J) (\frac{300 K- 280 K}{280K} )$
$|W| = 0.0714 \space J $