Question 737824
The monthly costs are $320 per month and $80 per month.  Because these costs are monthly use m to show that these costs occur monthly.
 
320m+80m=400m

In order to calculate how much this will cost per year substitute 12 for m because there are 12 months in a year
400m=400*(12)

400*(12)=  $4800 per year.

The yearly cost for the apartment is $4800.