James gets bored with his game so decides to play a different one.  That game promises 100 hours of gameplay but 80% of that is boring grinding.  However, the expansion does add another 30 hours of enjoyable gameplay.  How much enjoyable gameplay does James get?
James gets bored with his game so decides to play a different one. That game promises [NUMBER] hours of gameplay but [PERCENTAGE]% of that is boring grinding. However, the expansion does add another [NUMBER] hours of enjoyable gameplay. How much enjoyable gameplay does James get?
The first game was 100*.8=<<100*.8=80>>80 hours of grinding
So it was 100-80=<<100-80=20>>20 hours of good gameplay
The expansion brought the time of good gameplay to 20+30=<<20+30=50>>50 hours
#### 50