###Human: Nine adults went to a play with seven children. Adult tickets are $11 each and children's tickets are $7 each. How many dollars more did the adults' tickets cost in total than the children's tickets in total?, ### Assistant: Adults = 9 * 11 = 99
Children = 7 * 7 = 49
Difference: 99 - 49 = $50
The adults' tickets cost $50 more than the children's tickets. 
 So the answer is :  50