Final answer:
To make 21 cups of batter, you would need 168/5 cups of the other ingredients.
Step-by-step explanation:
To find out how much of each ingredient to use to make 21 cups of batter, we need to set up a proportion using the given information. We know that for every 2 cups of flour, we need 4/5 of the other ingredients. So we set up the proportion:
4/5 = x/2
We can solve this proportion by cross-multiplying:
4/5 * 2 = x
8/5 = x
So we need to use 8/5 cups of the other ingredients for every 2 cups of flour. To find out how much of each ingredient we need for 21 cups of batter, we can set up a new proportion:
8/5 = x/21
Again, we cross-multiply to solve the proportion:
8/5 * 21 = x
168/5 = x
Therefore, we need to use 168/5 cups of the other ingredients to make 21 cups of batter.