We know that total bill = rate per gallon times numbers of gallons used
So 17.60 = 0.55 times g
which get match to option (a) this is correct .
Now if we divide both sides by 0.55 we would be getting :
17.60 / 0.55 = g which is slightly different than option (b) ( because it is 55 in option b but actually it should be 0.55) so this one is incorrect .
let us now come back to option (a) 17.6 = 0.55 g
if flip the sides it becomes 0.55g = 17.6 which is same as option c option c is also correct .
Let us now divide both sides of option a by g^2 which makes it
17.6/ g^2 = 0.55 /g or 0.55/g = 17.6 /g^2 which matches only left side of option d but not right side of it so this is also not a correct option
Answer : only (a) and c are correct answer .
