In this question it is given that,
Let x = the number of gallons that Chris bought at the first station and y = the number of gallons Chris bought at the second station.
So we have
[tex] x+ y = 20 => x=20-y \\ 1.45x + 1.55y = 29.80 [/tex]
Substituting the value of x in the second equation, we will get
[tex] 1.45(20-y) + 1.55y = 29.80 \\ 29 -1.45y +1.55y = 29.80 \\ 0.10y = 0.80 \\ y= 8 gallons [/tex]
So the correct option is the second option .