Partial calculating average atomic mass

(isotopic mass × percentage abundance)÷100

47.99+847.07+608.36+7259.25

= 8761.67

8761.67÷100

=87.6167

+ 1

=87.62

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.