Answer:
1 1/5 cups
Step-by-step explanation:
Write and solve an equation of ratios here. Let x be the amount of butter needed if 3 cups of flour are used. Then, comparing the quantities of butter first (in the first column) and the quantities of flour second, we get the ratio
x 3 cups
------------- = -------------
(4/5) cup 2 cups
Cross-multiplying, we get:
2x = 12/5, or x = 6/5
You'll need 6/5 cups of butter, or 1 1/5 cups, if you're using 3 cups of flour.
