Android and back to main activity when time is up

I start a new activity from my main activity with

Intent i = new Intent(this, Game.class);
startActivity(i);

The game activity has a timer which counts dow开发者_StackOverflow社区n to 0. I would like to pop back to the main activity (killing the game activity).

How do I enact this?

(I've already defined onDestroy() etc. correctly in my game activity.)

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In the method that gets called when the timer is up call finish()