That sounds like Examination Day by Henry Slesar
Be careful if you go to the page and read the comments. It appears that a lot of the people posting were allowed to live, and even given civil service jobs, after the test.
Thanks for the link.
That was the one. It is a perfect short story and defines all teacher unionists and obamacrats. (aka feminists/weather underground/alinskys/democrat party)
You may specify by telephone, the voice droned on, whether you wish his body interred by the Government, or would you prefer a private burial place? The fee for Government burial is ten dollars.