Answer:
12 cups of salad are in the resulting mixture.
Explanation:
Four cups of a salad blend have 40% spinach,
So the amount of spinach is,

Let x amount of salad blend is mixed with 55% spinach.
So the amount of spinach is,

As both the cups were mixed, so the net amount will be (4+x) cups.
The result has 50% spinach, so the amount of spinach is,

As the amount of spinach is same, so







So, total amounts of mixture will be 4+8=12 cups.