For working h hours over 40, the lifeguard earns 12h dollars.
Then for h = 20 hours over 40, the lifegurad earns:
12(20) = 240
However, it is necessary to take into account that the life guard earns $320 per week for working 40 hours.
Then, the total amount of money he earns is:
320 + 240 = 560
The line that best represent the previous calculations is the graph G.
THere you can notice that for h=0 hours after 40 the earning are 320, and for h=20 hours the earning are 560.