###Human: Frankie and Carla played 30 games of ping pong against each other.  Frankie won half as many games as did Carla.  How many games did Carla win?, ### Assistant: Let x be the number of games that Frankie won.
Then the number of games Carla won would be 2*x.
And the sum of all the games would be x+2*x=30 games.
Thus, the expression simplifies to 3*x=30.
And the value of x=10 games.
Therefore, the number of Carla's wins would be 2x=20 games. 
 So the answer is :  20