Answer:
9/4 cup of sugar.
Explanation:
It has been given that
3/4 cup of sugar is needed to make a cake.
Now, she has decided to make a huge cup which needs to triple amount of ingredients that she needs in a single cake.
Therefore, in order to make the huge cake of her family she needs three times of 3/4 cup of sugar.
Hence,

Therefore, she needs 9/4 cup of sugar.