###Human: An opera house has 150 rows; each row has ten seats. The ticket costs $10 per show. How much did the opera house earn from one of the shows if 20% of the seats were not taken?, ### Assistant: The opera house has 150 x 10 = 1500 seats.
There are 1500 x 20/100 = 300 seats that were not taken.
The total number of seats taken was 1500 - 300 = 1200.
Therefore, the opera house earned $10 x 1200 = $12000 from one of the shows. 
 So the answer is :  12000