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.