Table: grand_prix_1971_3
Columns: driver
constructor
laps
time_retired
grid

Question: what is the grid when the time/retired is oil pressure and the laps are more than 50?
SQL: SELECT AVG("grid") FROM grand_prix_1971_3 WHERE "time_retired" = 'oil pressure' AND "laps" > 50

Question: what is the grid when the time/retired is 1:46:42.3?
SQL: SELECT SUM("grid") FROM grand_prix_1971_3 WHERE "time_retired" = '1:46:42.3'