The manager of a 100-unit apartment complex knows from experience that all units will be occupied if the rent is $800 per month. a market survey suggests that, on average, one additional unit will remain vacant for each $10 increase in rent. what rent should the manager charge to maximize revenue?

What can you determine about the solutions of this system

The u-drive rent-a-truck company plans to spend $13 million on 320 new vehicles. each commercial van will cost $25 comma 000, each small truck $50 comma 000, and each large truck  $80 comma 000. past experience shows that they need twice as many vans as small trucks. how many of each type of vehicle can they buy?

Meee i honestly dont know what this question talking about