Answer: 149 cartridges will be sold at 20 dollars per cartridge.
Step-by-step explanation:
Given: The projected sales volume of a video game cartridge is given by the function
, where <em>s</em> is the number of cartridges sold, in thousands; <em>p</em> is the price per cartridge, in dollars; and <em>a</em> is a constant.
Put s(p)=100000, p= 10, we get

i.e. 
Put p=20, we get

Hence, 149 cartridges will be sold at 20 dollars per cartridge.