Answer:
The y-intercept is 
The y-intercept represents the initial quantity of gas in the canister which is zero.
Step-by-step explanation:
The y-intercept is where the graph of the straight line touches the y-axis.
From the graph, the y-intercept is the origin (0,0).
Recall that the slope intercept form of a straight line is
, where
is the y-intercept in this case.
Since the graph represents the amount of gasoline in a canister after Joshua begins to fill it at the gas station pump, the y-intercept means the initial gallons of gas in the canister is zero.