The number of cups of flour per shortcake in Wyatt's recipe is given by
[tex] \frac{3.15}{9} =0.35[/tex]
The number of cups of flour per shortcake in Cora's recipe is given by
[tex] \frac{2.4}{8} =0.3[/tex]
The number of more cups of flour needed by Cora is given by 0.35 - 0.3 = 0.05 cups.