If the cut off fractions are 1 1/2, 3/4, 1/3 then these answers should be right.
(A) so if there is 1 1/2 cups of flour for 6 servings then you need to divide 1 1/2 by 6 to get 1/4 of a cup
(B) there are 1 1/12 cups of sugar (white & brown) then divide 1 1/12 by 6 to get 13/72 cups
(C) To make the recipe serve 9 people you could divide all the fractions by six to see how much would make one serving then multiply by 9.
the new fractions for 1 serving are 1/4, 1/8, and 1/18
when multiplied by 9 the fractions become 2 1/4 1 1/18 1/2
Hope i could help