Answer:
Ruby needs 7 combined.
Step-by-step explanation:
If she needs 1/4 cup of powdered milk for one batch, then we multiply 1/4 by 4 to see how much she needs for 4 batches, which is 4/4, or one whole.
If she needs 3/2 cups of whole wheat for one batch, then we multiply 3/2 by 4 to see how much she needs for 4 batches, which is 12/2, or 6.
Then we combine 6 and 1, which is 7.
