What are the rules for using modifiers with compound subjects?

What are the rules for using modifiers with compound subjects?

The rules for using modifiers with compound subjects are as follows:

1. When a modifier applies to both subjects equally, place the modifier before the compound subject.
Example: John and Mary quickly finished their homework.

2. When a modifier applies to only one of the subjects, place the modifier after the subject it modifies.
Example: John quickly finished his homework, but Mary took her time.

3. If the modifier applies to different aspects of each subject, it is best to use separate modifiers for each subject.
Example: John studied hard and Mary practiced diligently.