30 ipods were up for sale at the local electronic store. the store owner sold the first 20 ipods for at least $15 and he sold the next 9 ipods for at least $20. if the owner made a total revenue of $600 by selling these 30 ipods, how much must he have sold the last ipod for?

Respuesta :

He sold the last ipod for:
[tex]600 - 20 \times 15 - 9 \times 20 \\ = 600 - 300 - 180 \\ = 120[/tex]
Thus he had sold the last ipod for $120.