Answer
(a) $+1.2\times10^{5}J$
(b) $5.9\times10^{5}J$
Work Step by Step
Here we use the first law of thermodynamics $Q=\Delta U+W$ to find the solutions.
(a) $Q=\Delta U+W=>W=Q-\Delta U$
Let's plug known values into this equation
$W=-6.8\times10^{5}J-(-8\times10^{5}J)=+1.2\times10^{5}J$
The work that the first player does before =$+1.2\times10^{5}J$
leaving the game
(b) $Q=\Delta U+W$ ; Let's plug known values into this equation.
$Q=2.1\times10^{5}J+(-8\times10^{5}J)=-5.9\times10^{5}J$
The magnitude of the heat lost = $5.9\times10^{5}J$