(a) There are 1/4 cups of flour per serving
WORK: 1.5/6=1/4 (change 1 1/2 into decimal)
(b) **not sure** There are approximately .18 cups of sugar per serving.
WORK: 9/2+4/12=13/12 and then divide 13/12 by 6.
(c) You need 2 1/4 cups of flour to make 9 servings.
WORK: 1.5/2=.75
1.5+.75=2.25=2 1/4
(d) Someone would need to know the amount of sugar to properly make the recipe and if needed know how much to put if you wanted to split the recipe.