Question

There are two different compounds of sulfur and fluorine.

Answer 1

1.18 x 3 = 3.55 
find  ratio of F to F in each compound
.   according to law of multiple proportions  that the masses of one element which combine with a fixed mass of the second element are in a ratio of whole numbers.
now  F is  "one element" and S has  "fixed mass",
the ratio of F6 to Fx = 3:1 
thats why  x= 2
there is less F in SFx
  the ratio is 3:1.
 dividing 6 by 3 and you get 2