1/4barrel 2/3hour as a unit rate

distance covered by pamela in 9 l of fuel = 99km

let us apply unitary method here.

distance covered by pamela in 1 l of fuel =99/9 =11 km

now let us find distance covered by pamela if she has 12 l of fuel.

distance covered in 12 l = distance covered in 1 l of fuel * 12

we know that distance covered by here in 1 l is 11 km.

so distance covered in 12 l of fuel = 11*12 = 132 km.

is there any other information given for this problem? this is not enough information.

(x,y) it'll always be like that.

in this case x is grams and y is ounces.

if there were numbers there, like (5,3)

x would be 5 and y would be 3.

it would be r^2 - 2rs +s^2

assuming   you mean to square it