Let x represent the time played so far. Then the time remaining is x/3.
(Time remaining) + (time played so far) = 32 minutes total. Substituting,
x/3 + x = 32 min
4x/3 = 32 min
x = (3/4)(32 min) = 24 min
= time played so far
At this point the fraction of the game already passed is
24 min
---------- = 3/4 and this is equivalent to 75%.
32 min