To figure this out, first multiply $30 by 11 to see how much money will come out of the full price:
$30×11=$330.
Next, subtract $330 from $990.
$990–$330=$660
The fixed price for 11 televisions is $660. So, divide $660 by 11.
$660÷11=$60.
So the fixed amount that Gerry earns for each television is $60.
Hope this helps! :D