The problem doesn't say how many innings the starting pitcher played.
Starting pitcher = ? innings = x innings
1st relief pitcher = 1 inning
2nd relief pitcher = 2/3 inning
Total (starting + 1st + 2nd) = 5/3 + x
Closing pitcher = 9 - 5/3 - x
Closing pitcher = 27/3 - 5/3 - x
Closing pitcher = 22/3 - x
The closer played (7 1/3 - starting) innings.