Answer:
109 car stereos
Step-by-step explanation:
If 149 car stereos had a CD player (with or without a cassette player), and 40 car stereos had both a CD and a cassette player, the number of stereos with only a CD player is determined by:
[tex]CD_{only} = CD - Both\\CD_{only} =149-40\\CD_{only} =109\ car\ stereos[/tex]
109 car stereos had only a CD player.