Answer:
Part A:
We know that with 1/4 cup of butter, Ursula can make 1 batch of brownies. So since 1/2 is just 1/4 multiplied by 2, we know that Ursula can make 2 batches of Brownies for 1/2 cup of butter.
Part B:
1/2 cups of butter = 2 batches of brownies
1/4 cups of butter = 1 batch of brownies