CREATE TABLE table_71984 ("Church name" TEXT, "Location" TEXT, "Rebuilt" TEXT, "Date of demolition" FLOAT, "Subsuming parish" TEXT)

What is the location that has a date of demolition of 1940 and has a church named Christ Church Greyfriars?
SELECT "Location" FROM table_71984 WHERE "Date of demolition" = '1940' AND "Church name" = 'christ church greyfriars'
SELECT "Location" FROM "table_71984" WHERE "Church name" = 'christ church greyfriars' AND "Date of demolition" = '1940'