Wyatt uses 3.15 cups of flour in a recipe that makes 9 shortcakes. Cora uses 2.4 cups of flour in a recipe that makes 8 shortcakes. How much more flower per shortcake is needed for Cora's recipe?

For Wyatt's recipe the rate is:

r1 = 3.15 / 9

r1 = 0.35

For Cora's recipe the rate is:

r2 = 2.4 / 8

r2 = 0.3

The difference between both recipes is:

r1-r2 = 0.35 - 0.3 = 0.05

Answer:

0.05 cups of flour per shortcake less is needed for Cora's recipe