Table:
text: 1975 San Diego Chargers season
Schedule
Schedule
Week Date_ Opponent Result_ Attendance
11 November 30, 1975 at Denver Broncos L 13–10 44982
12 December 7, 1975 at Kansas City Chiefs W 28–20 46888
13 December 15, 1975 New York Jets W 24–16 49706
14 December 21, 1975 at Cincinnati Bengals L 47–17 46474

Question: What is the average week that the score w was 28-20 and 46,888+ attendance in the San Diego Chargers 1975 season?