Final answer:
To make a whole cake, you need 5/2 cups of flour.
Step-by-step explanation:
To find how many cups of flour are needed to make a whole cake, we need to determine the ratio of cups of flour to the fraction of the cake that requires the flour. We are given that it takes 1/2 cup of flour to make 1/5 of a cake.
To find the number of cups of flour needed for the entire cake, we can set up a proportion:
1/2 cup / 1/5 of cake = x cups / 1 whole cake
To solve the proportion, we can cross-multiply:
(1/2 cup) * (1 whole cake) = x cups * (1/5 of cake)
Simplifying, we get:
1/2 = x/5
To isolate the variable x, we can multiply both sides of the equation by 5:
5 * (1/2) = 5 * (x/5)
Simplifying further, we get:
5/2 = x
Therefore, we need 5/2 cups of flour to make a whole cake.